Merge pull request #1081 from MBombeck/fix/v1398-polish

Glucose bands, decimals, calendar dates and chart axes as the reader expects
2026-11-12 06:06:10 +00:00 · 2026-10-01 22:51:34 +02:00
commit 1399cca4d0
@@ -261,11 +261,11 @@
      "title": "Glukose-Übersicht (klinisch)",
      "colMetric": "Kennzahl",
      "colValue": "Wert",
-      "tirInRange": "Zeit im Zielbereich (70–180 mg/dl)",
-      "tirLow": "Niedrig (< 70 mg/dl)",
-      "tirVeryLow": "Sehr niedrig (< 54 mg/dl)",
-      "tirHigh": "Hoch (> 180 mg/dl)",
-      "tirVeryHigh": "Sehr hoch (> 250 mg/dl)",
+      "tirInRange": "Zeit im Zielbereich ({low}–{high} {unit})",
+      "tirLow": "Niedrig (< {low} {unit})",
+      "tirVeryLow": "Sehr niedrig (< {veryLow} {unit})",
+      "tirHigh": "Hoch (> {high} {unit})",
+      "tirVeryHigh": "Sehr hoch (> {veryHigh} {unit})",
      "mean": "Durchschnittliche Glukose",
      "gmi": "Glukose-Management-Indikator (GMI)",
      "eA1c": "Geschätzter HbA1c",
@@ -3440,7 +3440,7 @@
    },
    "bloodGlucose": {
      "title": "Blutzucker",
-      "description": "Deine Blutzuckerwerte im Zeitverlauf, in mg/dL.",
+      "description": "Deine Blutzuckerwerte im Zeitverlauf, in {unit}.",
      "chartTitle": "Blutzucker",
      "medianLabel": "Median Blutzucker",
      "emptyState": {
@@ -3461,7 +3461,7 @@
        "daysCountOne": "1 Tag",
        "tir": {
          "title": "Zeit im Zielbereich",
-          "caption": "Anteil der Messungen je Bereich (70–180 mg/dl ist das Ziel).",
+          "caption": "Anteil der Messungen je Bereich ({low}–{high} {unit} ist das Ziel).",
          "veryLow": "Sehr niedrig",
          "low": "Niedrig",
          "inRange": "Im Zielbereich",
@@ -297,11 +297,11 @@
      "title": "Glucose overview (clinical)",
      "colMetric": "Metric",
      "colValue": "Value",
-      "tirInRange": "Time in range (70–180 mg/dL)",
-      "tirLow": "Low (< 70 mg/dL)",
-      "tirVeryLow": "Very low (< 54 mg/dL)",
-      "tirHigh": "High (> 180 mg/dL)",
-      "tirVeryHigh": "Very high (> 250 mg/dL)",
+      "tirInRange": "Time in range ({low}–{high} {unit})",
+      "tirLow": "Low (< {low} {unit})",
+      "tirVeryLow": "Very low (< {veryLow} {unit})",
+      "tirHigh": "High (> {high} {unit})",
+      "tirVeryHigh": "Very high (> {veryHigh} {unit})",
      "mean": "Average glucose",
      "gmi": "Glucose Management Indicator (GMI)",
      "eA1c": "Estimated A1C",
@@ -3174,7 +3174,7 @@
        "headphoneAudioBody": "Headphone audio levels track how loudly you listen through earbuds or headphones, in decibels. Keeping the volume down and taking breaks protects your hearing over the long run.",
        "audioEventsBody": "Loud sound events flag moments when noise around you reached a level that can harm hearing with enough exposure. Frequent events are a cue to seek quieter surroundings or hearing protection.",
        "daylightBody": "Time in daylight is how long you spend in outdoor light each day. Regular daylight supports a healthy sleep-wake rhythm and mood (CDC 2024), and time outdoors is linked to eye health.",
-        "bloodGlucoseBody": "Blood glucose is the amount of sugar in your blood, the body's main energy source. It rises after eating and settles between meals. As general guidance for adults without diabetes, a fasting reading under 100 mg/dL is normal, 100–125 is prediabetes, and 126 or above falls in the diabetes range (ADA 2024). A single high reading does not diagnose — a clinician confirms with a repeat test, and people managing diabetes use different, clinician-set targets.",
+        "bloodGlucoseBody": "Blood glucose is the amount of sugar in your blood, the body's main energy source. It rises after eating and settles between meals. As general guidance for adults without diabetes, a fasting reading under {prediabetesFrom} {unit} is normal, {prediabetesFrom}–{prediabetesTo} is prediabetes, and {diabetesFrom} or above falls in the diabetes range (ADA 2024). A single high reading does not diagnose — a clinician confirms with a repeat test, and people managing diabetes use different, clinician-set targets.",
        "skinTemperatureBody": "Skin temperature here is the small nightly change in your wrist temperature from your own baseline, not an absolute fever reading. Shifts can track sleep, environment, illness, or menstrual-cycle phase.",
        "cardioFitnessBody": "VO₂ max is how much oxygen your body can use at peak effort — the best lab index of aerobic fitness, which wearables estimate indirectly. A higher or rising trend is a strong sign of cardiovascular health.",
        "cardioRecoveryBody": "Cardio recovery is how many beats per minute your heart rate falls in the first minute after you stop hard exercise. A bigger drop means your heart settles down faster, which is a sign of good fitness.",
@@ -3440,7 +3440,7 @@
    },
    "bloodGlucose": {
      "title": "Blood Glucose",
-      "description": "Your blood-glucose readings over time, in mg/dL.",
+      "description": "Your blood-glucose readings over time, in {unit}.",
      "chartTitle": "Blood glucose",
      "medianLabel": "Median glucose",
      "emptyState": {
@@ -3461,7 +3461,7 @@
        "daysCountOne": "1 day",
        "tir": {
          "title": "Time in range",
-          "caption": "Share of readings in each band (70–180 mg/dL is the target).",
+          "caption": "Share of readings in each band ({low}–{high} {unit} is the target).",
          "veryLow": "Very low",
          "low": "Low",
          "inRange": "In range",
@@ -261,11 +261,11 @@
      "title": "Resumen de glucosa (clínico)",
      "colMetric": "Métrica",
      "colValue": "Valor",
-      "tirInRange": "Tiempo en rango (70–180 mg/dl)",
-      "tirLow": "Bajo (< 70 mg/dl)",
-      "tirVeryLow": "Muy bajo (< 54 mg/dl)",
-      "tirHigh": "Alto (> 180 mg/dl)",
-      "tirVeryHigh": "Muy alto (> 250 mg/dl)",
+      "tirInRange": "Tiempo en rango ({low}–{high} {unit})",
+      "tirLow": "Bajo (< {low} {unit})",
+      "tirVeryLow": "Muy bajo (< {veryLow} {unit})",
+      "tirHigh": "Alto (> {high} {unit})",
+      "tirVeryHigh": "Muy alto (> {veryHigh} {unit})",
      "mean": "Glucosa media",
      "gmi": "Indicador de gestión de la glucosa (GMI)",
      "eA1c": "A1C estimada",
@@ -3440,7 +3440,7 @@
    },
    "bloodGlucose": {
      "title": "Glucosa en sangre",
-      "description": "Tus lecturas de glucosa en el tiempo, en mg/dL.",
+      "description": "Tus lecturas de glucosa en el tiempo, en {unit}.",
      "chartTitle": "Glucosa en sangre",
      "medianLabel": "Glucosa mediana",
      "emptyState": {
@@ -3461,7 +3461,7 @@
        "daysCountOne": "1 día",
        "tir": {
          "title": "Tiempo en rango",
-          "caption": "Proporción de mediciones en cada banda (70–180 mg/dl es el objetivo).",
+          "caption": "Proporción de mediciones en cada banda ({low}–{high} {unit} es el objetivo).",
          "veryLow": "Muy bajo",
          "low": "Bajo",
          "inRange": "En rango",
@@ -261,11 +261,11 @@
      "title": "Aperçu glycémique (clinique)",
      "colMetric": "Indicateur",
      "colValue": "Valeur",
-      "tirInRange": "Temps dans la cible (70–180 mg/dl)",
-      "tirLow": "Bas (< 70 mg/dl)",
-      "tirVeryLow": "Très bas (< 54 mg/dl)",
-      "tirHigh": "Élevé (> 180 mg/dl)",
-      "tirVeryHigh": "Très élevé (> 250 mg/dl)",
+      "tirInRange": "Temps dans la cible ({low}–{high} {unit})",
+      "tirLow": "Bas (< {low} {unit})",
+      "tirVeryLow": "Très bas (< {veryLow} {unit})",
+      "tirHigh": "Élevé (> {high} {unit})",
+      "tirVeryHigh": "Très élevé (> {veryHigh} {unit})",
      "mean": "Glycémie moyenne",
      "gmi": "Indicateur de gestion du glucose (GMI)",
      "eA1c": "HbA1c estimée",
@@ -3440,7 +3440,7 @@
    },
    "bloodGlucose": {
      "title": "Glycémie",
-      "description": "Vos relevés de glycémie au fil du temps, en mg/dL.",
+      "description": "Vos relevés de glycémie au fil du temps, en {unit}.",
      "chartTitle": "Glycémie",
      "medianLabel": "Glycémie médiane",
      "emptyState": {
@@ -3461,7 +3461,7 @@
        "daysCountOne": "1 jour",
        "tir": {
          "title": "Temps dans la cible",
-          "caption": "Part des mesures dans chaque plage (70–180 mg/dl est la cible).",
+          "caption": "Part des mesures dans chaque plage ({low}–{high} {unit} est la cible).",
          "veryLow": "Très bas",
          "low": "Bas",
          "inRange": "Dans la cible",
@@ -261,11 +261,11 @@
      "title": "Panoramica glicemia (clinica)",
      "colMetric": "Metrica",
      "colValue": "Valore",
-      "tirInRange": "Tempo nell'intervallo (70–180 mg/dl)",
-      "tirLow": "Basso (< 70 mg/dl)",
-      "tirVeryLow": "Molto basso (< 54 mg/dl)",
-      "tirHigh": "Alto (> 180 mg/dl)",
-      "tirVeryHigh": "Molto alto (> 250 mg/dl)",
+      "tirInRange": "Tempo nell'intervallo ({low}–{high} {unit})",
+      "tirLow": "Basso (< {low} {unit})",
+      "tirVeryLow": "Molto basso (< {veryLow} {unit})",
+      "tirHigh": "Alto (> {high} {unit})",
+      "tirVeryHigh": "Molto alto (> {veryHigh} {unit})",
      "mean": "Glicemia media",
      "gmi": "Indicatore di gestione del glucosio (GMI)",
      "eA1c": "A1C stimata",
@@ -3440,7 +3440,7 @@
    },
    "bloodGlucose": {
      "title": "Glicemia",
-      "description": "Le tue letture di glicemia nel tempo, in mg/dL.",
+      "description": "Le tue letture di glicemia nel tempo, in {unit}.",
      "chartTitle": "Glicemia",
      "medianLabel": "Glicemia mediana",
      "emptyState": {
@@ -3461,7 +3461,7 @@
        "daysCountOne": "1 giorno",
        "tir": {
          "title": "Tempo nel range",
-          "caption": "Quota di misurazioni in ciascuna fascia (70–180 mg/dl è l’obiettivo).",
+          "caption": "Quota di misurazioni in ciascuna fascia ({low}–{high} {unit} è l’obiettivo).",
          "veryLow": "Molto basso",
          "low": "Basso",
          "inRange": "Nel range",
@@ -297,11 +297,11 @@
      "title": "혈당 개요 (임상)",
      "colMetric": "지표",
      "colValue": "값",
-      "tirInRange": "목표 범위 내 시간 (70–180 mg/dL)",
-      "tirLow": "낮음 (< 70 mg/dL)",
-      "tirVeryLow": "매우 낮음 (< 54 mg/dL)",
-      "tirHigh": "높음 (> 180 mg/dL)",
-      "tirVeryHigh": "매우 높음 (> 250 mg/dL)",
+      "tirInRange": "목표 범위 내 시간 ({low}–{high} {unit})",
+      "tirLow": "낮음 (< {low} {unit})",
+      "tirVeryLow": "매우 낮음 (< {veryLow} {unit})",
+      "tirHigh": "높음 (> {high} {unit})",
+      "tirVeryHigh": "매우 높음 (> {veryHigh} {unit})",
      "mean": "평균 혈당",
      "gmi": "혈당 관리 지표 (GMI)",
      "eA1c": "추정 당화혈색소 (A1C)",
@@ -3174,7 +3174,7 @@
        "headphoneAudioBody": "헤드폰 음량은 이어폰이나 헤드폰으로 얼마나 크게 듣는지를 dB로 기록해요. 볼륨을 낮추고 중간중간 쉬어 주면 오래도록 청력을 지킬 수 있어요.",
        "audioEventsBody": "큰 소리 이벤트는 주변 소음이 충분히 노출될 경우 청력을 해칠 수 있는 수준에 도달한 순간을 표시해요. 자주 발생한다면 더 조용한 환경을 찾거나 청력 보호구를 쓰라는 신호예요.",
        "daylightBody": "햇빛 노출 시간은 하루에 야외 빛 속에서 보낸 시간이에요. 규칙적인 햇빛은 건강한 수면-각성 리듬과 기분에 도움이 되고(CDC 2024), 야외에서 보내는 시간은 눈 건강과도 연결돼요.",
-        "bloodGlucoseBody": "혈당은 몸의 주된 에너지원인 혈액 속 당의 양이에요. 식후에 올라가고 식사 사이에 가라앉아요. 당뇨가 없는 성인의 일반적인 기준으로 공복 혈당 100mg/dL 미만이 정상, 100~125는 당뇨 전 단계, 126 이상은 당뇨 범위예요(ADA 2024). 한 번 높게 나왔다고 진단되지는 않아요 — 임상의가 재검으로 확인하고, 당뇨를 관리하는 사람은 임상의가 정한 다른 목표를 써요.",
+        "bloodGlucoseBody": "혈당은 몸의 주된 에너지원인 혈액 속 당의 양이에요. 식후에 올라가고 식사 사이에 가라앉아요. 당뇨가 없는 성인의 일반적인 기준으로 공복 혈당 {prediabetesFrom} {unit} 미만이 정상, {prediabetesFrom}~{prediabetesTo}는 당뇨 전 단계, {diabetesFrom} 이상은 당뇨 범위예요(ADA 2024). 한 번 높게 나왔다고 진단되지는 않아요 — 임상의가 재검으로 확인하고, 당뇨를 관리하는 사람은 임상의가 정한 다른 목표를 써요.",
        "skinTemperatureBody": "여기서 피부 온도는 절대적인 발열 수치가 아니라 본인 기준값 대비 밤사이 손목 온도의 작은 변화예요. 이 변화는 수면·환경·질병·생리 주기 단계를 반영할 수 있어요.",
        "cardioFitnessBody": "VO₂ max는 최대 노력에서 몸이 쓸 수 있는 산소량으로, 유산소 체력의 가장 좋은 실험실 지표이고 웨어러블은 이를 간접 추정해요. 값이 높거나 올라가는 추이는 심혈관 건강의 강력한 신호예요.",
        "cardioRecoveryBody": "심박 회복은 격한 운동을 멈춘 뒤 1분 동안 심박수가 분당 몇 회 떨어지는지예요. 많이 떨어질수록 심장이 더 빨리 안정된다는 뜻이고, 체력이 좋다는 신호예요.",
@@ -3440,7 +3440,7 @@
    },
    "bloodGlucose": {
      "title": "혈당",
-      "description": "시간에 따른 혈당 측정값이에요(mg/dL).",
+      "description": "시간에 따른 혈당 측정값이에요({unit}).",
      "chartTitle": "혈당",
      "medianLabel": "혈당 중앙값",
      "emptyState": {
@@ -3461,7 +3461,7 @@
        "daysCountOne": "1일",
        "tir": {
          "title": "목표 범위 내 시간",
-          "caption": "구간별 측정값 비율이에요(목표는 70~180mg/dL).",
+          "caption": "구간별 측정값 비율이에요(목표는 {low}~{high} {unit}).",
          "veryLow": "매우 낮음",
          "low": "낮음",
          "inRange": "목표 범위",
@@ -261,11 +261,11 @@
      "title": "Przegląd glukozy (kliniczny)",
      "colMetric": "Wskaźnik",
      "colValue": "Wartość",
-      "tirInRange": "Czas w zakresie (70–180 mg/dl)",
-      "tirLow": "Niski (< 70 mg/dl)",
-      "tirVeryLow": "Bardzo niski (< 54 mg/dl)",
-      "tirHigh": "Wysoki (> 180 mg/dl)",
-      "tirVeryHigh": "Bardzo wysoki (> 250 mg/dl)",
+      "tirInRange": "Czas w zakresie ({low}–{high} {unit})",
+      "tirLow": "Niski (< {low} {unit})",
+      "tirVeryLow": "Bardzo niski (< {veryLow} {unit})",
+      "tirHigh": "Wysoki (> {high} {unit})",
+      "tirVeryHigh": "Bardzo wysoki (> {veryHigh} {unit})",
      "mean": "Średnia glukoza",
      "gmi": "Wskaźnik zarządzania glukozą (GMI)",
      "eA1c": "Szacowane HbA1c",
@@ -3440,7 +3440,7 @@
    },
    "bloodGlucose": {
      "title": "Poziom glukozy",
-      "description": "Twoje odczyty glukozy w czasie, w mg/dL.",
+      "description": "Twoje odczyty glukozy w czasie, w {unit}.",
      "chartTitle": "Poziom glukozy",
      "medianLabel": "Mediana glukozy",
      "emptyState": {
@@ -3461,7 +3461,7 @@
        "daysCountOne": "1 dzień",
        "tir": {
          "title": "Czas w zakresie",
-          "caption": "Udział pomiarów w każdym przedziale (70–180 mg/dl to cel).",
+          "caption": "Udział pomiarów w każdym przedziale ({low}–{high} {unit} to cel).",
          "veryLow": "Bardzo niski",
          "low": "Niski",
          "inRange": "W zakresie",
@@ -10,7 +10,7 @@
 *
 * Mutation check: add `unit="kg"` back to any swept page and this goes red.
 */
-import { readFileSync } from "node:fs";
+import { readdirSync, readFileSync } from "node:fs";
 import { join } from "node:path";

 import { stripComments, walkSourceFiles } from "./helpers/source-files";
@@ -515,3 +515,74 @@ describe("unit-preference display guard — AI and Coach producers", () => {
    expect(offenders).toEqual([]);
  });
 });
+
+/**
+ * Locale strings that may name a glucose unit literally, each with the reason
+ * it is not a reading shown in the reader's unit. Keys are dotted paths and
+ * apply to every locale bundle.
+ */
+const GLUCOSE_UNIT_LITERAL_ALLOWLIST: Record<string, string> = {
+  "dashboard.metric.unit.glucose":
+    "the unit token the dashboard summary wire hands the native client; the web resolves the glucose unit from the account instead",
+  "labs.biomarker.form.unitPlaceholder":
+    "an example of a free-text lab unit in an input placeholder, not a reading",
+};
+
+const GLUCOSE_UNIT_LITERAL = /mg\/dl|mmol\/l\b/i;
+
+function flattenStrings(
+  node: unknown,
+  path: string,
+  out: Array<[string, string]>,
+): void {
+  if (typeof node === "string") {
+    out.push([path, node]);
+  } else if (node && typeof node === "object") {
+    for (const [key, value] of Object.entries(node)) {
+      flattenStrings(value, path ? `${path}.${key}` : key, out);
+    }
+  }
+}
+
+describe("unit-preference display guard — locale strings", () => {
+  const MESSAGES = join(process.cwd(), "messages");
+  const bundles = readdirSync(MESSAGES).filter((f) => f.endsWith(".json"));
+
+  it("reads every locale bundle", () => {
+    expect(bundles.length).toBeGreaterThanOrEqual(7);
+  });
+
+  it("no locale string fixes a glucose unit outside the allowlist", () => {
+    // A sentence that prints "70–180 mg/dL" shows mg/dL to a reader who
+    // chose mmol/L. Band and unit go in as parameters (`glucoseBandParams`).
+    const offenders: string[] = [];
+    for (const file of bundles) {
+      const entries: Array<[string, string]> = [];
+      flattenStrings(
+        JSON.parse(readFileSync(join(MESSAGES, file), "utf8")),
+        "",
+        entries,
+      );
+      for (const [key, value] of entries) {
+        if (key in GLUCOSE_UNIT_LITERAL_ALLOWLIST) continue;
+        if (GLUCOSE_UNIT_LITERAL.test(value)) offenders.push(`${file}: ${key}`);
+      }
+    }
+    expect(offenders).toEqual([]);
+  });
+
+  it("every allowlisted key still exists and still names a unit", () => {
+    // An entry whose string was reworded or removed is a stale exemption.
+    const en: Array<[string, string]> = [];
+    flattenStrings(
+      JSON.parse(readFileSync(join(MESSAGES, "en.json"), "utf8")),
+      "",
+      en,
+    );
+    const byKey = new Map(en);
+    const stale = Object.keys(GLUCOSE_UNIT_LITERAL_ALLOWLIST).filter(
+      (key) => !GLUCOSE_UNIT_LITERAL.test(byKey.get(key) ?? ""),
+    );
+    expect(stale).toEqual([]);
+  });
+});
@@ -5,8 +5,12 @@ import { Droplet } from "lucide-react";
 import { HealthKitMetricPage } from "@/components/insights/healthkit-metric-page";
 import { GlucoseClinicalPanel } from "@/components/insights/glucose/glucose-clinical-panel";
 import { useAuth } from "@/hooks/use-auth";
-import { useTranslations } from "@/lib/i18n/context";
-import { MGDL_PER_MMOL, resolveGlucoseUnit } from "@/lib/glucose";
+import { useFormatters, useTranslations } from "@/lib/i18n/context";
+import {
+  glucoseBandParams,
+  MGDL_PER_MMOL,
+  resolveGlucoseUnit,
+} from "@/lib/glucose";

 /**
 * v1.7.0 — `/insights/blood-glucose`.
@@ -27,6 +31,7 @@ import { MGDL_PER_MMOL, resolveGlucoseUnit } from "@/lib/glucose";
 export default function InsightsBlutzuckerPage() {
  const { user } = useAuth();
  const { t } = useTranslations();
+  const fmt = useFormatters();
  const glucoseUnit = resolveGlucoseUnit(user?.glucoseUnit ?? null);
  const isMmol = glucoseUnit === "mmol/L";

@@ -38,6 +43,9 @@ export default function InsightsBlutzuckerPage() {
      chartKey="bloodGlucose"
      i18nPrefix="insights.bloodGlucose"
      explainerMetric="bloodGlucose"
+      // The definition names the fasting cut-points; they follow the
+      // reader's glucose unit like the chart does.
+      explainerParams={glucoseBandParams(glucoseUnit, fmt.number)}
      color="var(--chart-3)"
      unit={glucoseUnit}
      yAxisUnit={glucoseUnit}
@@ -1,11 +1,8 @@
 "use client";

+import { useCalendarDate } from "@/hooks/use-calendar-date";
 import { useState, useMemo, useEffect, useRef } from "react";
-import {
-  useDisplayTimezone,
-  useFormatters,
-  useTranslations,
-} from "@/lib/i18n/context";
+import { useDisplayTimezone, useTranslations } from "@/lib/i18n/context";
 import { heatmapDays } from "@/lib/charts/heatmap-days";

 interface DailyData {
@@ -83,12 +80,11 @@ export function ComplianceHeatmap({
  stretch = false,
 }: ComplianceHeatmapProps) {
  const { t } = useTranslations();
-  const fmt = useFormatters();
  const timeZone = useDisplayTimezone();
-  // Day keys are UTC-anchored "YYYY-MM-DD"; format at noon UTC so the
-  // locale-aware renderer never lands a day off in either direction.
-  const formatDay = (dateKey: string) =>
-    fmt.date(new Date(`${dateKey}T12:00:00Z`));
+  // Day keys are calendar dates ("YYYY-MM-DD"), read as such in every zone.
+  // A noon-UTC instant formatted in the reader's zone was a day late from
+  // UTC+12 to UTC+14.
+  const formatDay = useCalendarDate();
  const containerRef = useRef<HTMLDivElement | null>(null);
  const [containerWidth, setContainerWidth] = useState(0);
  const [tooltip, setTooltip] = useState<{
@@ -71,6 +71,7 @@ import {
  type MetricWindowStats,
 } from "@/lib/charts/window-stats";
 import { shouldFireDataReady } from "@/lib/charts/data-ready-latch";
+import { axisUnitSuffix } from "@/lib/charts/axis-unit";

 // The range tabs select a CALENDAR-DAY window ending now — `days: 7` is
 // "the last 7 days", not "the last 7 readings". The labels said "points"
@@ -1982,8 +1983,8 @@ export function HealthChart({
                        : String(value)
                    }
                    unit={
-                      showYAxisUnit && (yAxisUnit ?? unit)
-                        ? ` ${yAxisUnit ?? unit}`
+                      showYAxisUnit
+                        ? axisUnitSuffix(yAxisUnit ?? unit)
                        : undefined
                    }
                  />
@@ -1,11 +1,8 @@
 "use client";

+import { useCalendarDate } from "@/hooks/use-calendar-date";
 import { useState, useMemo, useEffect, useRef } from "react";
-import {
-  useDisplayTimezone,
-  useFormatters,
-  useTranslations,
-} from "@/lib/i18n/context";
+import { useDisplayTimezone, useTranslations } from "@/lib/i18n/context";
 import { heatmapDays } from "@/lib/charts/heatmap-days";
 import { moodLabelKeyForScore } from "@/lib/mood/labels";

@@ -66,12 +63,11 @@ export function MoodHeatmap({
  stretch = false,
 }: MoodHeatmapProps) {
  const { t } = useTranslations();
-  const fmt = useFormatters();
  const timeZone = useDisplayTimezone();
-  // Day keys are UTC-anchored "YYYY-MM-DD"; format at noon UTC so the
-  // locale-aware renderer never lands a day off in either direction.
-  const formatDay = (dateKey: string) =>
-    fmt.date(new Date(`${dateKey}T12:00:00Z`));
+  // Day keys are calendar dates ("YYYY-MM-DD"), read as such in every zone.
+  // A noon-UTC instant formatted in the reader's zone was a day late from
+  // UTC+12 to UTC+14.
+  const formatDay = useCalendarDate();
  const containerRef = useRef<HTMLDivElement | null>(null);
  const [containerWidth, setContainerWidth] = useState(0);
  const [tooltip, setTooltip] = useState<{
@@ -0,0 +1,106 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { renderToStaticMarkup } from "react-dom/server";
+
+import { makeFormatters } from "@/lib/format-locale";
+import { I18nProvider } from "@/lib/i18n/context";
+import type { InboundDocumentDto } from "@/lib/validations/inbound-documents";
+
+/**
+ * A document's filing date is a calendar date. The card used to anchor it at
+ * 12:00 UTC and format that instant in the reader's zone, which shows the
+ * next day from UTC+12 to UTC+14. A document without a filing date shows its
+ * upload day, an instant, in the reader's zone.
+ *
+ * Server rendering cannot see the reader's profile zone, so the formatter
+ * hook is handed one.
+ */
+const zone = vi.hoisted(() => ({ current: "UTC" }));
+
+vi.mock("@/lib/i18n/context", async (importOriginal) => {
+  const actual = await importOriginal<typeof import("@/lib/i18n/context")>();
+  return {
+    ...actual,
+    useFormatters: () => makeFormatters("en", zone.current, "AUTO", "AUTO"),
+  };
+});
+
+const { DocumentCard } = await import("../document-card");
+
+function doc(overrides: Partial<InboundDocumentDto>): InboundDocumentDto {
+  return {
+    id: "doc-1",
+    kind: "IMAGING",
+    title: "Scan",
+    filename: "scan.pdf",
+    mimeType: "application/pdf",
+    byteSize: 1000,
+    status: "STORED",
+    providerType: null,
+    reportDate: null,
+    documentDate: null,
+    errorReason: null,
+    factCount: 0,
+    pendingCount: 0,
+    conditionLinks: [],
+    encounterLinks: [],
+    servingClass: "inline",
+    hasContentIndex: false,
+    contentIndexSource: null,
+    lastIndexAttemptAt: null,
+    lastIndexOutcome: null,
+    hasThumbnail: false,
+    sourceSystem: null,
+    sourceId: null,
+    createdAt: "2025-10-04T20:30:00.000Z",
+    updatedAt: "2025-10-04T20:30:00.000Z",
+    ...overrides,
+  };
+}
+
+function render(document: InboundDocumentDto) {
+  const noop = () => {};
+  return renderToStaticMarkup(
+    <I18nProvider initialLocale="en">
+      <DocumentCard
+        document={document}
+        selected={false}
+        onToggleSelected={noop}
+        onOpen={noop}
+        highlighted={false}
+      />
+    </I18nProvider>,
+  );
+}
+
+const previousTz = process.env.TZ;
+
+describe("document card dates across zones", () => {
+  afterEach(() => {
+    process.env.TZ = previousTz;
+    zone.current = "UTC";
+  });
+
+  describe.each(["Pacific/Kiritimati", "America/Los_Angeles"])(
+    "in %s",
+    (tz) => {
+      beforeEach(() => {
+        process.env.TZ = tz;
+        zone.current = tz;
+      });
+
+      it("shows the filing date as stated", () => {
+        const html = render(doc({ documentDate: "2025-10-04" }));
+        expect(html).toContain("10/04/2025");
+        expect(html).not.toContain("10/05/2025");
+        expect(html).not.toContain("10/03/2025");
+      });
+    },
+  );
+
+  it("shows the upload day in the reader's zone when no filing date is set", () => {
+    // 20:30 UTC on 4 October is 10:30 on 5 October in Kiritimati.
+    process.env.TZ = "Pacific/Kiritimati";
+    zone.current = "Pacific/Kiritimati";
+    expect(render(doc({ documentDate: null }))).toContain("10/05/2025");
+  });
+});
@@ -16,6 +16,7 @@
 * whole card is clickable through an invisible overlay button; the checkbox
 * floats above it.
 */
+import { useDocumentDate } from "@/components/documents/use-document-date";
 import { Check, Download, Loader2, X } from "lucide-react";
 import { useEffect, useRef, useState } from "react";

@@ -24,14 +25,13 @@ import { Button } from "@/components/ui/button";
 import { Card, CardContent } from "@/components/ui/card";
 import { Checkbox } from "@/components/ui/checkbox";
 import { useFencedObjectUrl } from "@/hooks/use-fenced-object-url";
-import { useFormatters, useTranslations } from "@/lib/i18n/context";
+import { useTranslations } from "@/lib/i18n/context";
 import { cn } from "@/lib/utils";
 import type { InboundDocumentDto } from "@/lib/validations/inbound-documents";
 import { DOCUMENT_KIND_ICONS } from "./document-kind-meta";
 import type { UploadQueueItem } from "./use-document-upload";
 import {
  documentCardKeyAction,
-  documentDateKey,
  formatBytes,
  isDocumentProcessing,
 } from "./vault-utils";
@@ -71,7 +71,7 @@ export function DocumentCard({
  onPrefetch?: (id: string) => void;
 }) {
  const { t, locale } = useTranslations();
-  const format = useFormatters();
+  const documentDate = useDocumentDate();

  // A preview thumbnail that fails to load (still rendering, decrypt error,
  // 404) falls back to the kind icon — never a broken image.
@@ -101,7 +101,7 @@ export function DocumentCard({
  const title =
    document.title ?? document.filename ?? t("documents.card.untitled");
  const Icon = DOCUMENT_KIND_ICONS[document.kind];
-  const date = format.date(`${documentDateKey(document)}T12:00:00.000Z`);
+  const date = documentDate(document);
  const size = formatBytes(document.byteSize, locale);
  const showFilename =
    document.filename !== null && document.filename !== title;
@@ -16,6 +16,7 @@
 * copy. A Share action in the footer opens the clinician share-link create
 * flow (shared `ShareLinkCreateForm`) with this document pre-attached.
 */
+import { useCalendarDate } from "@/hooks/use-calendar-date";
 import { useRecordCapabilities } from "@/hooks/use-record-capabilities";
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import {
@@ -344,6 +345,7 @@ export function DocumentDetailSheet({
 }) {
  const { t, tCount, locale } = useTranslations();
  const format = useFormatters();
+  const calendarDate = useCalendarDate();
  const queryClient = useQueryClient();
  // v1.28.52 (Documents R3) — the vault "Ask the Coach" action opens the REAL
  // fenced coach conversation in the shared side drawer (scoped to this
@@ -695,7 +697,7 @@ export function DocumentDetailSheet({
    ? t(`documents.kind.${suggestion.kind}`)
    : null;
  const suggestionDateLabel = suggestion?.documentDate
-    ? format.date(`${suggestion.documentDate}T12:00:00.000Z`)
+    ? calendarDate(suggestion.documentDate)
    : null;

  const title = doc?.title ?? doc?.filename ?? t("documents.card.untitled");
@@ -24,6 +24,7 @@
 * rejected (stated in the copy); an unverified low-confidence fact gets NO
 * decision and stays pending rather than being silently discarded.
 */
+import { useCalendarDate } from "@/hooks/use-calendar-date";
 import { useState } from "react";
 import { FlaskConical, Loader2, ScanSearch } from "lucide-react";
 import { toast } from "sonner";
@@ -34,7 +35,7 @@ import { Checkbox } from "@/components/ui/checkbox";
 import { DateField } from "@/components/ui/date-field";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
-import { useFormatters, useTranslations } from "@/lib/i18n/context";
+import { useTranslations } from "@/lib/i18n/context";
 import { cn } from "@/lib/utils";
 import type {
  ConditionFactData,
@@ -209,7 +210,7 @@ function FactRow({
  failure: string | null;
 }) {
  const { t } = useTranslations();
-  const format = useFormatters();
+  const calendarDate = useCalendarDate();
  const editFact = useEditFact();
  const [verifying, setVerifying] = useState(false);
  const [draft, setDraft] = useState<VerifyDraft>(() => draftFor(fact));
@@ -260,7 +261,7 @@ function FactRow({
          </p>
          <p className="text-muted-foreground text-xs">
            {typeLabel}
-            {date ? ` · ${format.date(`${date}T12:00:00.000Z`)}` : ""}
+            {date ? ` · ${calendarDate(date)}` : ""}
            {isObservation &&
            (fact.data as ObservationFactData).referenceText ? (
              <>
@@ -12,6 +12,7 @@
 * Shows one page (50) of matches — the search input is the way to reach an
 * older document, mirroring the vault's own recall model.
 */
+import { useDocumentDate } from "@/components/documents/use-document-date";
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import { Check, Search } from "lucide-react";
 import { useEffect, useRef, useState } from "react";
@@ -22,7 +23,7 @@ import { ResponsiveSheet } from "@/components/ui/responsive-sheet";
 import { Skeleton } from "@/components/ui/skeleton";
 import { QueryErrorRow } from "@/components/ui/query-error-row";
 import { apiGet, apiPost } from "@/lib/api/api-fetch";
-import { useFormatters, useTranslations } from "@/lib/i18n/context";
+import { useTranslations } from "@/lib/i18n/context";
 import { invalidateKeys, queryKeys } from "@/lib/query-keys";
 import { cn } from "@/lib/utils";
 import type {
@@ -30,7 +31,6 @@ import type {
  InboundDocumentDto,
 } from "@/lib/validations/inbound-documents";
 import { DOCUMENT_KIND_ICONS } from "./document-kind-meta";
-import { documentDateKey } from "./vault-utils";

 interface ListPage {
  documents: InboundDocumentDto[];
@@ -47,7 +47,7 @@ export function DocumentLinkPicker({
  onOpenChange: (open: boolean) => void;
 }) {
  const { t } = useTranslations();
-  const format = useFormatters();
+  const documentDate = useDocumentDate();
  const queryClient = useQueryClient();

  const [searchDraft, setSearchDraft] = useState("");
@@ -174,7 +174,7 @@ export function DocumentLinkPicker({
                        {title}
                      </span>
                      <span className="text-muted-foreground block text-xs">
-                        {format.date(`${documentDateKey(doc)}T12:00:00.000Z`)}
+                        {documentDate(doc)}
                      </span>
                    </span>
                    <Check
@@ -14,6 +14,7 @@
 * module-gated surfaces never leak. An episode without documents shows a
 * quiet one-line affordance, not a teaching empty state.
 */
+import { useDocumentDate } from "@/components/documents/use-document-date";
 import { useQuery } from "@tanstack/react-query";
 import { FolderOpen, Link2, Upload } from "lucide-react";
 import Link from "next/link";
@@ -28,13 +29,12 @@ import { Skeleton } from "@/components/ui/skeleton";
 import { useAuth } from "@/hooks/use-auth";
 import { useRecordCapabilities } from "@/hooks/use-record-capabilities";
 import { apiGet } from "@/lib/api/api-fetch";
-import { useFormatters, useTranslations } from "@/lib/i18n/context";
+import { useTranslations } from "@/lib/i18n/context";
 import { queryKeys } from "@/lib/query-keys";
 import type { InboundDocumentDto } from "@/lib/validations/inbound-documents";
 import { DocumentLinkPicker } from "./document-link-picker";
 import { ImportFromSourceButton } from "./sources/import-from-source-button";
 import { DOCUMENT_KIND_ICONS } from "./document-kind-meta";
-import { documentDateKey } from "./vault-utils";

 /** Compact preview size — "Alle anzeigen" carries the long tail. */
 const PREVIEW_LIMIT = 5;
@@ -46,7 +46,7 @@ interface ListPage {

 export function EpisodeDocumentsCard({ episodeId }: { episodeId: string }) {
  const { t } = useTranslations();
-  const format = useFormatters();
+  const documentDate = useDocumentDate();
  const { user } = useAuth();
  // Linking a document to an episode writes through
  // `POST /api/documents/inbound/bulk`, the same endpoint the vault gates on
@@ -137,7 +137,7 @@ export function EpisodeDocumentsCard({ episodeId }: { episodeId: string }) {
                          {title}
                        </span>
                        <span className="text-muted-foreground shrink-0 text-xs">
-                          {format.date(`${documentDateKey(doc)}T12:00:00.000Z`)}
+                          {documentDate(doc)}
                        </span>
                      </Link>
                    </ListRow>
@@ -27,6 +27,7 @@
 * With either, a document already in HealthLog can be picked too: it is not
 * stored twice, it is linked or handed to the form.
 */
+import { useCalendarDate } from "@/hooks/use-calendar-date";
 import {
  useInfiniteQuery,
  useQuery,
@@ -66,7 +67,7 @@ import {
  type DocumentSourceSearchDto,
  type DocumentSourceTagDto,
 } from "@/lib/documents/sources/types";
-import { useFormatters, useTranslations } from "@/lib/i18n/context";
+import { useTranslations } from "@/lib/i18n/context";
 import { invalidateKeys, queryKeys } from "@/lib/query-keys";
 import { cn } from "@/lib/utils";
 import type { InboundDocumentKindValue } from "@/lib/validations/inbound-documents";
@@ -119,7 +120,7 @@ export function DocumentSourcePicker({
  onImported,
 }: DocumentSourcePickerProps) {
  const { t, locale } = useTranslations();
-  const format = useFormatters();
+  const calendarDate = useCalendarDate();
  const queryClient = useQueryClient();

  const [system, setSystem] = useState<DocumentPickerSystem | null>(null);
@@ -581,7 +582,7 @@ export function DocumentSourcePicker({
              const run = runs.get(row.sourceId);
              const allowed = selectable(row);
              const meta = [
-                row.date ? format.date(`${row.date}T12:00:00.000Z`) : null,
+                row.date ? calendarDate(row.date) : null,
                row.sizeBytes !== null
                  ? formatBytes(row.sizeBytes, locale)
                  : null,
@@ -0,0 +1,27 @@
+"use client";
+
+import { useCallback } from "react";
+
+import { useCalendarDate } from "@/hooks/use-calendar-date";
+import { useFormatters } from "@/lib/i18n/context";
+import type { InboundDocumentDto } from "@/lib/validations/inbound-documents";
+
+/**
+ * The date a document files under, as a reader sees it. A filing date is a
+ * calendar date and reads the same in every zone; a document without one
+ * shows the day it was uploaded, which is an instant and reads in the
+ * reader's zone.
+ */
+export function useDocumentDate(): (
+  doc: Pick<InboundDocumentDto, "documentDate" | "createdAt">,
+) => string {
+  const fmt = useFormatters();
+  const calendarDate = useCalendarDate();
+  return useCallback(
+    (doc) =>
+      doc.documentDate
+        ? calendarDate(doc.documentDate)
+        : fmt.date(doc.createdAt),
+    [fmt, calendarDate],
+  );
+}
@@ -2,6 +2,8 @@ import { describe, it, expect, vi } from "vitest";
 import { renderToStaticMarkup } from "react-dom/server";

 import { I18nProvider } from "@/lib/i18n/context";
+import { glucoseBandParams } from "@/lib/glucose";
+import { makeFormatters } from "@/lib/format-locale";
 import { SubPageShell } from "../sub-page-shell";

 vi.mock("next/navigation", () => ({
@@ -68,6 +70,27 @@ describe("<SubPageShell>", () => {
    );
  });

+  it("fills the explainer's figures from the explainer parameters", () => {
+    // The glucose definition names the fasting cut-points; a reader on
+    // mmol/L reads them in mmol/L, never a fixed "100 mg/dL".
+    const html = render(
+      <SubPageShell
+        title="Blood glucose"
+        explainerMetric="bloodGlucose"
+        explainerParams={glucoseBandParams(
+          "mmol/L",
+          makeFormatters("en", "UTC", "AUTO", "AUTO").number,
+        )}
+      >
+        <span />
+      </SubPageShell>,
+    );
+    expect(html).toContain(
+      "a fasting reading under 5.6 mmol/L is normal, 5.6–6.9 is prediabetes, and 7.0 or above",
+    );
+    expect(html).not.toContain("{");
+  });
+
  it("no longer paints the round `?` explainer trigger next to the heading", () => {
    const html = render(
      <SubPageShell title="Blood pressure" explainerMetric="bloodPressure">
@@ -148,6 +148,35 @@ describe("<GlucoseClinicalPanel> asserted state", () => {
    expect(html).toContain("J-index");
  });

+  it("states the target band in the reader's unit and number format", () => {
+    // The caption used to print "70–180 mg/dL" to every reader, beside
+    // values the panel had already converted to mmol/L.
+    authMock.mockReturnValue({
+      user: { glucoseUnit: "mmol/L" },
+      isAuthenticated: true,
+    });
+    analyticsMock.mockReturnValue({
+      isLoading: false,
+      data: { glucoseClinical: assertedClinical(), glucoseByContext: {} },
+    });
+    const de = render(<GlucoseClinicalPanel />, "de");
+    expect(de).toContain("(3,9–10,0 mmol/L ist das Ziel)");
+    expect(de).not.toMatch(/mg\/dl/i);
+    // Mean, GMI and eA1C read with the German decimal comma.
+    expect(de).not.toMatch(/>\d+\.\d+</);
+    expect(de).toMatch(
+      />\d+,\d<\/span><span class="text-muted-foreground text-xs">mmol\/L/,
+    );
+
+    authMock.mockReturnValue({
+      user: { glucoseUnit: "mg/dL" },
+      isAuthenticated: true,
+    });
+    expect(render(<GlucoseClinicalPanel />)).toContain(
+      "(70–180 mg/dL is the target)",
+    );
+  });
+
  it("flags the CV badge unstable at CV% >= 36", () => {
    // wide spread → CV well above 36
    const values = Array.from({ length: 20 }, (_, i) =>
@@ -4,7 +4,7 @@ import { useId, useState } from "react";
 import { ChevronDown } from "lucide-react";

 import { InfoPopover } from "@/components/ui/info-popover";
-import { useTranslations } from "@/lib/i18n/context";
+import { useFormatters, useTranslations } from "@/lib/i18n/context";
 import { cn } from "@/lib/utils";
 import type { GlucoseClinicalMetrics } from "@/lib/analytics/glucose-metrics";
 import type { DataSummary } from "@/lib/analytics/trends";
@@ -49,11 +49,12 @@ export function GlucoseAdvancedDisclosure({
  fractionDigits = 1,
 }: GlucoseAdvancedDisclosureProps) {
  const { t } = useTranslations();
+  const number = useFormatters().number;
  const [open, setOpen] = useState(false);
  const regionId = useId();

  const fmt = (v: number | null) =>
-    v === null ? "—" : v.toFixed(fractionDigits);
+    v === null ? "—" : number(v, fractionDigits);

  const contexts = Object.entries(byContext ?? {}).filter(
    ([, s]) => s && s.count > 0,
@@ -12,8 +12,12 @@ import { LearnMoreLink } from "@/components/ui/learn-more-link";
 import { Skeleton } from "@/components/ui/skeleton";
 import { useAuth } from "@/hooks/use-auth";
 import { useAnalyticsQuery } from "@/lib/queries/use-analytics-query";
-import { useTranslations } from "@/lib/i18n/context";
-import { convertGlucose, resolveGlucoseUnit } from "@/lib/glucose";
+import { useFormatters, useTranslations } from "@/lib/i18n/context";
+import {
+  convertGlucose,
+  glucoseBandParams,
+  resolveGlucoseUnit,
+} from "@/lib/glucose";
 import type { DataSummary } from "@/lib/analytics/trends";
 import { GlucoseTirBar } from "./glucose-tir-bar";
 import { GlucoseAdvancedDisclosure } from "./glucose-advanced-disclosure";
@@ -41,6 +45,7 @@ import { GlucoseAdvancedDisclosure } from "./glucose-advanced-disclosure";
 export function GlucoseClinicalPanel() {
  const { user, isAuthenticated } = useAuth();
  const { t } = useTranslations();
+  const fmt = useFormatters();
  const query = useAnalyticsQuery({});

  const glucoseUnit = resolveGlucoseUnit(user?.glucoseUnit ?? null);
@@ -77,7 +82,7 @@ export function GlucoseClinicalPanel() {

  const formatGlucoseValue = (mgdl: number): string => {
    const v = convertGlucose(mgdl, glucoseUnit);
-    return isMmol ? v.toFixed(1) : String(Math.round(v));
+    return fmt.number(v, isMmol ? 1 : 0);
  };

  // Learning state — calm, never asserting TIR / GMI off thin data.
@@ -158,7 +163,10 @@ export function GlucoseClinicalPanel() {
            </div>
            <GlucoseTirBar distribution={dist} />
            <p className="text-muted-foreground text-xs">
-              {t("insights.bloodGlucose.clinical.tir.caption")}
+              {t(
+                "insights.bloodGlucose.clinical.tir.caption",
+                glucoseBandParams(glucoseUnit, fmt.number),
+              )}
            </p>
          </section>
        ) : null}
@@ -181,7 +189,7 @@ export function GlucoseClinicalPanel() {
              icon={<Activity className="h-3.5 w-3.5" aria-hidden="true" />}
              label={t("insights.bloodGlucose.clinical.gmi.label")}
              help={t("insights.bloodGlucose.clinical.gmi.help")}
-              value={clinical.gmi.toFixed(1)}
+              value={fmt.number(clinical.gmi, 1)}
              unit="%"
            />
          ) : null}
@@ -190,7 +198,7 @@ export function GlucoseClinicalPanel() {
              icon={<TrendingUp className="h-3.5 w-3.5" aria-hidden="true" />}
              label={t("insights.bloodGlucose.clinical.eA1c.label")}
              help={t("insights.bloodGlucose.clinical.eA1c.help")}
-              value={clinical.estimatedA1c.toFixed(1)}
+              value={fmt.number(clinical.estimatedA1c, 1)}
              unit="%"
            />
          ) : null}
@@ -153,6 +153,8 @@ export interface HealthKitMetricPageProps {
   * Resolves `insights.subPage.explainer.<explainerMetric>{Title,Body}`.
   */
  explainerMetric?: string;
+  /** Interpolation values for the explainer sentence (`SubPageShell`). */
+  explainerParams?: Record<string, string>;
  /**
   * v1.8.5 W5 — when set, renders `<MetricTargetSummary slug=…>` beneath
   * the chart. Used by blood glucose, whose per-context ADA / DDG bands
@@ -227,6 +229,7 @@ export function HealthKitMetricPage({
  coachPrefill,
  valueScale,
  explainerMetric,
+  explainerParams,
  targetSummarySlug,
  statusMetric,
  statIcon,
@@ -334,7 +337,10 @@ export function HealthKitMetricPage({
      : rawSummary;

  const title = t(`${i18nPrefix}.title`);
-  const description = t(`${i18nPrefix}.description`);
+  // A description that names its unit ("in mg/dL") reads the resolved one.
+  const description = t(`${i18nPrefix}.description`, {
+    unit: resolvedUnit ?? "",
+  });

  // v1.12.7 — in-flight skeleton. The page consumed only `{data, isEmpty}`
  // before, so the ~30 HealthKit sub-pages painted nothing until the
@@ -347,6 +353,7 @@ export function HealthKitMetricPage({
        title={title}
        description={description}
        explainerMetric={explainerMetric}
+        explainerParams={explainerParams}
        statStrip={<StatStripSkeleton />}
      >
        <ChartSkeleton />
@@ -364,6 +371,7 @@ export function HealthKitMetricPage({
        title={title}
        description={description}
        explainerMetric={explainerMetric}
+        explainerParams={explainerParams}
      >
        <QueryErrorRow
          slot="healthkit-metric-error"
@@ -389,6 +397,7 @@ export function HealthKitMetricPage({
        title={title}
        description={description}
        explainerMetric={explainerMetric}
+        explainerParams={explainerParams}
      >
        <MetricEmptyState
          icon={emptyStateIcon}
@@ -406,6 +415,7 @@ export function HealthKitMetricPage({
      title={title}
      description={description}
      explainerMetric={explainerMetric}
+      explainerParams={explainerParams}
      statStrip={
        <MetricStatStrip
          summary={summary}
@@ -24,6 +24,7 @@ import { TileHeader } from "@/components/insights/tile-header";
 import { Button } from "@/components/ui/button";
 import { QueryErrorCard } from "@/components/ui/query-error-card";
 import { Skeleton } from "@/components/ui/skeleton";
+import { axisUnitSuffix } from "@/lib/charts/axis-unit";
 import {
  BUCKET_MINUTES,
  type IntradayHrBucket,
@@ -300,7 +301,7 @@ export function IntradayPulseChart({
                tick={{ fontSize: 11, fill: "var(--muted-foreground)" }}
                tickLine={false}
                axisLine={false}
-                unit=" bpm"
+                unit={axisUnitSuffix("bpm")}
                width={52}
              />
              <Tooltip
@@ -70,6 +70,11 @@ export interface SubPageShellProps {
   * one- to two-sentence definition, no tap required.
   */
  explainerMetric?: string;
+  /**
+   * Interpolation values for the explainer sentence, for a definition that
+   * names figures in the reader's own unit (the glucose cut-points).
+   */
+  explainerParams?: Record<string, string>;
  /**
   * v1.4.27 MB7 / CF-35 — opt-in programmatic focus on mount.
   *
@@ -155,6 +160,7 @@ export function SubPageShell({
  badge,
  description,
  explainerMetric,
+  explainerParams,
  focusOnMount = false,
  statStrip,
  coachReadStrip,
@@ -385,7 +391,10 @@ export function SubPageShell({
              data-slot="metric-explainer-inline"
              className="text-foreground text-sm leading-relaxed"
            >
-              {t(`insights.subPage.explainer.${explainerMetric}Body`)}
+              {t(
+                `insights.subPage.explainer.${explainerMetric}Body`,
+                explainerParams,
+              )}
            </p>
          ) : null}
          {description && !explainerMetric ? (
@@ -0,0 +1,110 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { renderToStaticMarkup } from "react-dom/server";
+import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
+
+import { makeFormatters } from "@/lib/format-locale";
+import { I18nProvider } from "@/lib/i18n/context";
+import type { LabResultDto } from "../types";
+
+/**
+ * A reading imported from a report that states only its date is stored at
+ * 12:00 UTC. Formatted in the reader's zone it read as the next day from
+ * UTC+12 to UTC+14. A reading typed with its time of day is an instant and
+ * keeps reading in the reader's zone.
+ *
+ * Server rendering cannot see the reader's profile zone, so the test hands
+ * it over the two ways the app reads it: the formatter hook and the
+ * mirrored zone the legacy helpers read.
+ */
+const zone = vi.hoisted(() => ({ current: "UTC" }));
+
+vi.mock("@/lib/timezone-mirror", async (importOriginal) => ({
+  ...(await importOriginal<typeof import("@/lib/timezone-mirror")>()),
+  readStoredTimezone: () => zone.current,
+}));
+vi.mock("@/lib/i18n/context", async (importOriginal) => {
+  const actual = await importOriginal<typeof import("@/lib/i18n/context")>();
+  return {
+    ...actual,
+    useFormatters: () => makeFormatters("en", zone.current, "AUTO", "AUTO"),
+  };
+});
+vi.mock("@/lib/api/api-fetch", () => ({
+  apiGet: () => new Promise(() => {}),
+  apiDelete: vi.fn(),
+  apiPost: vi.fn(),
+  apiPut: vi.fn(),
+}));
+
+const { LabHistoryList } = await import("../lab-history-list");
+
+function reading(id: string, takenAt: string): LabResultDto {
+  return {
+    id,
+    biomarkerId: "bm-1",
+    panel: null,
+    analyte: "TSH",
+    value: 1.8,
+    valueText: null,
+    unit: "mIU/L",
+    referenceLow: 0.4,
+    referenceHigh: 4,
+    catalogReferenceLow: 0.4,
+    catalogReferenceHigh: 4,
+    sourceReferenceLow: null,
+    sourceReferenceHigh: null,
+    sourceReferenceText: null,
+    referenceOrigin: "catalog",
+    referenceDivergesFromCatalog: false,
+    takenAt,
+    source: "MANUAL",
+    hasNote: false,
+    rangeStatus: "in-range",
+    createdAt: takenAt,
+    updatedAt: takenAt,
+  } as LabResultDto;
+}
+
+function render(readings: LabResultDto[]) {
+  return renderToStaticMarkup(
+    <QueryClientProvider client={new QueryClient()}>
+      <I18nProvider initialLocale="en">
+        <LabHistoryList readings={readings} />
+      </I18nProvider>
+    </QueryClientProvider>,
+  );
+}
+
+const previousTz = process.env.TZ;
+
+describe("lab reading dates across zones", () => {
+  afterEach(() => {
+    process.env.TZ = previousTz;
+    zone.current = "UTC";
+  });
+
+  describe.each(["Pacific/Kiritimati", "America/Los_Angeles"])(
+    "in %s",
+    (tz) => {
+      beforeEach(() => {
+        process.env.TZ = tz;
+        zone.current = tz;
+      });
+
+      it("shows a date-only reading on its stated date", () => {
+        const html = render([reading("r1", "2025-10-04T12:00:00.000Z")]);
+        expect(html).toContain("10/04/2025");
+        expect(html).not.toContain("10/05/2025");
+        expect(html).not.toContain("10/03/2025");
+      });
+    },
+  );
+
+  it("dates a reading typed with its time of day in the reader's zone", () => {
+    // 20:30 UTC on 4 October is 10:30 on 5 October in Kiritimati.
+    process.env.TZ = "Pacific/Kiritimati";
+    zone.current = "Pacific/Kiritimati";
+    const html = render([reading("r1", "2025-10-04T20:30:00.000Z")]);
+    expect(html).toContain("10/05/2025");
+  });
+});
@@ -7,9 +7,10 @@ import { LabReferenceRangeBar } from "../lab-reference-range-bar";

 function render(
  props: Partial<React.ComponentProps<typeof LabReferenceRangeBar>> = {},
+  locale: "en" | "de" = "en",
 ) {
  return renderToStaticMarkup(
-    <I18nProvider initialLocale="en">
+    <I18nProvider initialLocale={locale}>
      <LabReferenceRangeBar
        value={72}
        referenceLow={60}
@@ -45,4 +46,15 @@ describe("<LabReferenceRangeBar>", () => {
    expect(render({ referenceLow: null })).toContain('aria-label="≤100 bpm"');
    expect(render({ referenceHigh: null })).toContain('aria-label="≥60 bpm"');
  });
+
+  it("prints the reading and its range in the reader's number format", () => {
+    const html = render(
+      { value: 1.8333, referenceLow: 0.4, referenceHigh: 4.05, unit: "mIU/L" },
+      "de",
+    );
+    expect(html).toContain('aria-label="0,4–4,05 mIU/L"');
+    // Lab precision: at most two decimals, then the locale's separator.
+    expect(html).toContain("1,83 mIU/L");
+    expect(html).not.toMatch(/\d\.\d+ mIU\/L/);
+  });
 });
@@ -13,12 +13,12 @@ import { ResponsiveSheet } from "@/components/ui/responsive-sheet";
 import { Skeleton } from "@/components/ui/skeleton";
 import { apiDelete, apiGet, apiPut } from "@/lib/api/api-fetch";
 import { formatReferenceRange } from "@/lib/labs/reference-range";
-import { formatLabValue } from "@/lib/labs/format-value";
 import { useTranslations } from "@/lib/i18n/context";
 import { queryKeys } from "@/lib/query-keys";

 import { BiomarkerForm } from "./biomarker-form";
 import type { BiomarkerDto, BiomarkerListResponse } from "./types";
+import { useLabNumber } from "./use-lab-format";

 /**
 * v1.18.1 — the Biomarker catalog manager. v1.22 — compact editable rows.
@@ -42,6 +42,7 @@ import type { BiomarkerDto, BiomarkerListResponse } from "./types";
 */
 export function BiomarkerManager() {
  const { t } = useTranslations();
+  const labNumber = useLabNumber();
  const queryClient = useQueryClient();
  const [formOpen, setFormOpen] = useState(false);
  const [editing, setEditing] = useState<BiomarkerDto | null>(null);
@@ -101,7 +102,7 @@ export function BiomarkerManager() {
    const range = formatReferenceRange(
      marker.lowerBound,
      marker.upperBound,
-      formatLabValue,
+      labNumber,
    );
    return (
      <li
@@ -16,12 +16,12 @@ import {
 import { Button } from "@/components/ui/button";
 import { CHART_HEIGHT_PX } from "@/lib/charts/constants";
 import { prefersReducedMotion } from "@/lib/charts/reduced-motion";
-import { formatLabValue } from "@/lib/labs/format-value";
 import { formatReferenceRange } from "@/lib/labs/reference-range";
 import { useTranslations, useFormatters } from "@/lib/i18n/context";

 import { RichChartTooltip, type RichTooltipRow } from "../charts/chart-tooltip";
 import type { LabResultDto } from "./types";
+import { useLabNumber } from "./use-lab-format";

 /**
 * v1.18.1 — per-biomarker trend chart, in the dashboard's visual language.
@@ -91,6 +91,7 @@ export function LabBiomarkerChart({
  upperBound: number | null;
 }) {
  const { t } = useTranslations();
+  const labNumber = useLabNumber();
  const fmt = useFormatters();
  const [range, setRange] = useState<RangeKey>("365");
  // Capture "now" once at mount so the recency filter stays pure across
@@ -224,7 +225,7 @@ export function LabBiomarkerChart({
                tick={{ fontSize: 11, fill: "var(--muted-foreground)" }}
                stroke="var(--border)"
                width={44}
-                tickFormatter={(v: number) => formatLabValue(v)}
+                tickFormatter={(v: number) => labNumber(v)}
              />
              {/* Reference window — muted band + dashed bounds. No alarm
                  colour: the in/out verdict is shown by the neutral badge,
@@ -302,7 +303,7 @@ export function LabBiomarkerChart({
                  const rows: RichTooltipRow[] = [
                    {
                      name: t("labs.chart.valueLabel"),
-                      value: `${formatLabValue(point.value)} ${unit}`,
+                      value: `${labNumber(point.value)} ${unit}`,
                      color: primary,
                    },
                  ];
@@ -317,7 +318,7 @@ export function LabBiomarkerChart({
                        `${formatReferenceRange(
                          point.referenceLow,
                          point.referenceHigh,
-                          formatLabValue,
+                          labNumber,
                        )} ${unit}`.trim(),
                      color: secondary,
                    });
@@ -27,12 +27,12 @@ import {
  parseReferenceRange,
 } from "@/lib/labs/parse-reference-range";
 import { formatReferenceRange } from "@/lib/labs/reference-range";
-import { formatLabValue } from "@/lib/labs/format-value";
 import { EncounterSuggestionField } from "@/components/encounters/encounter-suggestion-field";
 import { useTranslations } from "@/lib/i18n/context";
 import { queryKeys } from "@/lib/query-keys";

 import { BiomarkerForm } from "./biomarker-form";
+import { useLabNumber } from "./use-lab-format";
 import type {
  BiomarkerDto,
  BiomarkerListResponse,
@@ -135,6 +135,7 @@ export function LabForm({
  footerSlot,
 }: LabFormProps) {
  const { t } = useTranslations();
+  const labNumber = useLabNumber();
  const recordName = useActiveRecordName();
  const queryClient = useQueryClient();
  const formId = useId();
@@ -325,11 +326,7 @@ export function LabForm({
  }

  const referenceText = selected
-    ? formatReferenceRange(
-        selected.lowerBound,
-        selected.upperBound,
-        formatLabValue,
-      )
+    ? formatReferenceRange(selected.lowerBound, selected.upperBound, labNumber)
    : "";

  // What the typed string resolved to, shown back so the user can see whether
@@ -342,7 +339,7 @@ export function LabForm({
      : `${formatReferenceRange(
          parsedSourceRange.low,
          parsedSourceRange.high,
-          formatLabValue,
+          labNumber,
        )} ${selected?.unit ?? ""}`.trim()
    : "";

@@ -28,7 +28,6 @@ import { Textarea } from "@/components/ui/textarea";
 import { useTableSort } from "@/hooks/use-table-sort";
 import { apiDelete, apiGet, apiPost, apiPut } from "@/lib/api/api-fetch";
 import { localizedApiError } from "@/lib/api/localized-error";
-import { formatDateShort } from "@/lib/format";
 import { formatLabReading } from "@/lib/labs/format-value";
 import { resolveNoteForUpdate } from "@/lib/labs/note-update";
 import { useTranslations } from "@/lib/i18n/context";
@@ -38,6 +37,7 @@ import { ReferenceRangeBadge } from "./reference-range-badge";
 import { LabReferenceRangeBar } from "./lab-reference-range-bar";
 import { SourceRangeNote } from "./source-range-note";
 import type { LabResultDetailDto, LabResultDto } from "./types";
+import { useLabDate, useLabNumber } from "./use-lab-format";

 const NOTE_MAX_LENGTH = 2000;

@@ -77,6 +77,8 @@ function parseDecimal(raw: string): number | null {
 */
 export function LabHistoryList({ readings }: { readings: LabResultDto[] }) {
  const { t } = useTranslations();
+  const labNumber = useLabNumber();
+  const labDate = useLabDate();
  const { canManageDomain } = useRecordCapabilities();
  const canManageLabs = canManageDomain("labs");
  const queryClient = useQueryClient();
@@ -353,7 +355,7 @@ export function LabHistoryList({ readings }: { readings: LabResultDto[] }) {
          <li key={r.id} className="flex items-start gap-3 py-3">
            <div className="min-w-0 flex-1 space-y-2">
              <div className="font-semibold tabular-nums">
-                {formatLabReading(r)}
+                {formatLabReading(r, labNumber)}
              </div>
              <LabReferenceRangeBar
                value={r.value}
@@ -362,9 +364,7 @@ export function LabHistoryList({ readings }: { readings: LabResultDto[] }) {
                unit={r.unit}
              />
              <div className="text-muted-foreground flex flex-wrap items-center gap-x-2 gap-y-1 text-sm">
-                <span className="whitespace-nowrap">
-                  {formatDateShort(r.takenAt, true)}
-                </span>
+                <span className="whitespace-nowrap">{labDate(r.takenAt)}</span>
                <ReferenceRangeBadge status={r.rangeStatus} />
                {r.hasNote ? (
                  <span className="text-xs">{t("labs.hasNote")}</span>
@@ -421,7 +421,7 @@ export function LabHistoryList({ readings }: { readings: LabResultDto[] }) {
              <TableRow key={r.id}>
                <TableCell className="font-semibold tabular-nums">
                  <div className="space-y-2">
-                    <span>{formatLabReading(r)}</span>
+                    <span>{formatLabReading(r, labNumber)}</span>
                    <LabReferenceRangeBar
                      value={r.value}
                      referenceLow={r.referenceLow}
@@ -431,7 +431,7 @@ export function LabHistoryList({ readings }: { readings: LabResultDto[] }) {
                  </div>
                </TableCell>
                <TableCell className="text-muted-foreground text-sm whitespace-nowrap">
-                  {formatDateShort(r.takenAt, true)}
+                  {labDate(r.takenAt)}
                </TableCell>
                <TableCell>
                  <div className="flex flex-col items-start gap-1">
@@ -13,15 +13,15 @@ import { EmptyState } from "@/components/ui/empty-state";
 import { QueryErrorCard } from "@/components/ui/query-error-card";
 import { Skeleton } from "@/components/ui/skeleton";
 import { apiGet } from "@/lib/api/api-fetch";
-import { formatDate } from "@/lib/format";
 import { formatReferenceRange } from "@/lib/labs/reference-range";
-import { formatLabReading, formatLabValue } from "@/lib/labs/format-value";
+import { formatLabReading } from "@/lib/labs/format-value";
 import { useTranslations } from "@/lib/i18n/context";
 import { cn } from "@/lib/utils";
 import { queryKeys } from "@/lib/query-keys";
 import { applyOrder, useModuleListPrefs } from "@/lib/module-list-prefs";

 import { LabTrendSparkline } from "./lab-trend-sparkline";
+import { useLabDate, useLabNumber } from "./use-lab-format";
 import { LabReferenceRangeBar } from "./lab-reference-range-bar";
 import { ReferenceRangeBadge } from "./reference-range-badge";
 import { SourceRangeNote } from "./source-range-note";
@@ -122,6 +122,8 @@ const MOBILE_CELL = {

 export function LabList({ onAddFirst }: { onAddFirst?: () => void } = {}) {
  const { t } = useTranslations();
+  const labNumber = useLabNumber();
+  const labDate = useLabDate();
  const { canWriteDomain } = useRecordCapabilities();
  const canAddLab = canWriteDomain("labs");
  const { prefs } = useModuleListPrefs("labs");
@@ -255,9 +257,9 @@ export function LabList({ onAddFirst }: { onAddFirst?: () => void } = {}) {
                  </div>
                  <div className="text-muted-foreground flex flex-wrap items-center gap-x-2 text-xs">
                    <span className="text-foreground font-semibold tabular-nums">
-                      {formatLabReading(group.latest)}
+                      {formatLabReading(group.latest, labNumber)}
                    </span>
-                    <span>{formatDate(group.latest.takenAt)}</span>
+                    <span>{labDate(group.latest.takenAt)}</span>
                  </div>
                </div>
              );
@@ -373,7 +375,7 @@ export function LabList({ onAddFirst }: { onAddFirst?: () => void } = {}) {
                <div className="flex items-end justify-between gap-3">
                  <div className="text-muted-foreground flex min-w-0 flex-1 flex-wrap items-center gap-x-2 text-sm">
                    <span className="text-foreground font-semibold tabular-nums">
-                      {formatLabReading(group.latest)}
+                      {formatLabReading(group.latest, labNumber)}
                    </span>
                    {group.latest.value !== null &&
                    (group.latest.referenceLow !== null ||
@@ -383,7 +385,7 @@ export function LabList({ onAddFirst }: { onAddFirst?: () => void } = {}) {
                        {formatReferenceRange(
                          group.latest.referenceLow,
                          group.latest.referenceHigh,
-                          formatLabValue,
+                          labNumber,
                        )}
                      </span>
                    ) : null}
@@ -392,7 +394,7 @@ export function LabList({ onAddFirst }: { onAddFirst?: () => void } = {}) {
                      className="text-xs"
                    />
                    <span className="text-xs">
-                      {formatDate(group.latest.takenAt)}
+                      {labDate(group.latest.takenAt)}
                    </span>
                    {group.readings.length > 1 ? (
                      <span className="text-xs">
@@ -2,6 +2,8 @@

 import { RangeBar } from "@/components/targets/range-bar";

+import { useLabNumber } from "./use-lab-format";
+
 /**
 * v1.37.34 — compact reference-range visualization for saved lab readings.
 *
@@ -20,6 +22,7 @@ export function LabReferenceRangeBar({
  referenceHigh: number | null;
  unit: string;
 }) {
+  const labNumber = useLabNumber();
  const hasLow = referenceLow !== null && Number.isFinite(referenceLow);
  const hasHigh = referenceHigh !== null && Number.isFinite(referenceHigh);
  if (
@@ -37,10 +40,10 @@ export function LabReferenceRangeBar({
  const min = referenceLow ?? referenceHigh! - scale;
  const max = referenceHigh ?? referenceLow! + scale;
  const rangeLabel = !hasLow
-    ? `≤${referenceHigh} ${unit}`
+    ? `≤${labNumber(referenceHigh!)} ${unit}`
    : !hasHigh
-      ? `≥${referenceLow} ${unit}`
-      : `${referenceLow}–${referenceHigh} ${unit}`;
+      ? `≥${labNumber(referenceLow!)} ${unit}`
+      : `${labNumber(referenceLow!)}–${labNumber(referenceHigh!)} ${unit}`;

  return (
    <div
@@ -55,6 +58,7 @@ export function LabReferenceRangeBar({
        unit={unit}
        compact
        tone="lab"
+        formatValue={labNumber}
        minLabel={referenceLow === null ? null : undefined}
        maxLabel={referenceHigh === null ? null : undefined}
      />
@@ -1,10 +1,10 @@
 "use client";

-import { formatLabValue } from "@/lib/labs/format-value";
 import { formatReferenceRange } from "@/lib/labs/reference-range";
 import { useTranslations } from "@/lib/i18n/context";

 import type { LabResultDto } from "./types";
+import { useLabNumber } from "./use-lab-format";

 /**
 * The reference window a reading's own report printed, shown wherever that
@@ -40,6 +40,7 @@ export function SourceRangeNote({
  className?: string;
 }) {
  const { t } = useTranslations();
+  const labNumber = useLabNumber();
  if (reading.referenceOrigin !== "source") return null;

  const printed =
@@ -47,13 +48,13 @@ export function SourceRangeNote({
    `${formatReferenceRange(
      reading.referenceLow,
      reading.referenceHigh,
-      formatLabValue,
+      labNumber,
    )} ${reading.unit}`.trim();

  const catalog = formatReferenceRange(
    reading.catalogReferenceLow,
    reading.catalogReferenceHigh,
-    formatLabValue,
+    labNumber,
  );

  return (
@@ -0,0 +1,40 @@
+"use client";
+
+import { useCallback } from "react";
+
+import { useCalendarDate } from "@/hooks/use-calendar-date";
+import { useFormatters } from "@/lib/i18n/context";
+import { formatLabValue, type LabNumberFormat } from "@/lib/labs/format-value";
+import { isNoonUtcAnchor } from "@/lib/tz/date-only";
+
+/**
+ * A lab value in the reader's number format, trimmed the way every lab
+ * surface trims it (whole numbers bare, at most two decimals).
+ */
+export function useLabNumber(): LabNumberFormat {
+  const fmt = useFormatters();
+  return useCallback(
+    (value: number) => formatLabValue(value, (n) => fmt.number(n)),
+    [fmt],
+  );
+}
+
+/**
+ * The date a lab reading was taken. A reading entered by hand carries its
+ * time of day and is dated in the reader's zone; one imported from a report
+ * that states only the date is stored at noon UTC and is dated by that
+ * calendar date, so it does not move to the next day east of UTC+12.
+ */
+export function useLabDate(): (takenAt: string) => string {
+  const fmt = useFormatters();
+  const calendarDate = useCalendarDate();
+  return useCallback(
+    (takenAt: string) => {
+      const instant = new Date(takenAt);
+      return isNoonUtcAnchor(instant)
+        ? calendarDate(instant)
+        : fmt.date(instant);
+    },
+    [fmt, calendarDate],
+  );
+}
@@ -26,6 +26,7 @@ import {
 } from "recharts";
 import { makeFormatters } from "@/lib/format-locale";
 import { useDateFormatPreference, useTranslations } from "@/lib/i18n/context";
+import { axisUnitSuffix } from "@/lib/charts/axis-unit";

 export interface EfficacyChartTarget {
  label: string;
@@ -169,7 +170,7 @@ export function EfficacyChart({
            tickLine={false}
            axisLine={false}
            width={40}
-            unit={unitSuffix ? ` ${unitSuffix}` : undefined}
+            unit={axisUnitSuffix(unitSuffix)}
          />
          <YAxis
            yAxisId="adherence"
@@ -13,6 +13,7 @@
 * the central factory; reads unwrap `(await res.json()).data` via `apiGet`.
 * No write happens here — attaching is the create mutation's job.
 */
+import { useDocumentDate } from "@/components/documents/use-document-date";
 import { useQuery } from "@tanstack/react-query";
 import { Check, Search } from "lucide-react";
 import { useEffect, useRef, useState } from "react";
@@ -23,9 +24,8 @@ import { QueryErrorRow } from "@/components/ui/query-error-row";
 import { ResponsiveSheet } from "@/components/ui/responsive-sheet";
 import { Skeleton } from "@/components/ui/skeleton";
 import { DOCUMENT_KIND_ICONS } from "@/components/documents/document-kind-meta";
-import { documentDateKey } from "@/components/documents/vault-utils";
 import { apiGet } from "@/lib/api/api-fetch";
-import { useFormatters, useTranslations } from "@/lib/i18n/context";
+import { useTranslations } from "@/lib/i18n/context";
 import { queryKeys } from "@/lib/query-keys";
 import { cn } from "@/lib/utils";
 import type { InboundDocumentDto } from "@/lib/validations/inbound-documents";
@@ -55,7 +55,7 @@ export function ShareDocumentPicker({
  max: number;
 }) {
  const { t } = useTranslations();
-  const format = useFormatters();
+  const documentDate = useDocumentDate();

  const [searchDraft, setSearchDraft] = useState("");
  const [query, setQuery] = useState("");
@@ -195,7 +195,7 @@ export function ShareDocumentPicker({
                        {title}
                      </span>
                      <span className="text-muted-foreground block text-xs">
-                        {format.date(`${documentDateKey(doc)}T12:00:00.000Z`)}
+                        {documentDate(doc)}
                      </span>
                    </span>
                    <Check
@@ -11,9 +11,12 @@ import { EDGE_PADDING_PERCENT, RangeBar } from "../range-bar";
 * extraction is provably side-effect-free.
 */

-function render(props: Parameters<typeof RangeBar>[0]) {
+function render(
+  props: Parameters<typeof RangeBar>[0],
+  locale: "en" | "de" = "en",
+) {
  return renderToStaticMarkup(
-    <I18nProvider initialLocale="en">
+    <I18nProvider initialLocale={locale}>
      <RangeBar {...props} />
    </I18nProvider>,
  );
@@ -93,4 +96,17 @@ describe("<RangeBar>", () => {
    expect(html).toContain('role="img"');
    expect(html).toContain('aria-label="Current: 72 bpm');
  });
+
+  it("prints value, bounds and delta in the reader's number format", () => {
+    // A German reader saw "61.3 kg" under a German interface.
+    const html = render(
+      { value: 72.4, min: 50.5, max: 70.25, unit: "kg" },
+      "de",
+    );
+    expect(html).toContain("50,5 kg");
+    expect(html).toContain("70,25 kg");
+    expect(html).toContain("72,4 kg");
+    expect(html).toContain("2,2 kg");
+    expect(html).not.toMatch(/\d\.\d+ kg/);
+  });
 });
@@ -6,7 +6,7 @@ import {
  TooltipProvider,
  TooltipTrigger,
 } from "@/components/ui/tooltip";
-import { useTranslations } from "@/lib/i18n/context";
+import { useFormatters, useTranslations } from "@/lib/i18n/context";

 /**
 * A horizontal range bar with green/yellow/red zones showing where
@@ -28,6 +28,12 @@ export interface RangeBarProps {
  tone?: "target" | "lab";
  minLabel?: string | null;
  maxLabel?: string | null;
+  /**
+   * How a value or bound is printed. Defaults to the reader's locale number
+   * format; a surface with its own precision rule (lab values trim to two
+   * decimals) passes it here so the bar and the row beside it agree.
+   */
+  formatValue?: (value: number) => string;
 }

 /**
@@ -49,8 +55,13 @@ export function RangeBar({
  tone = "target",
  minLabel,
  maxLabel,
+  formatValue,
 }: RangeBarProps) {
  const { t } = useTranslations();
+  const fmt = useFormatters();
+  // Every printed number goes through the locale formatter: a German reader
+  // sees "61,3 kg", not "61.3 kg".
+  const show = formatValue ?? ((v: number) => fmt.number(v));
  const isLab = tone === "lab";

  const span = max - min;
@@ -132,8 +143,8 @@ export function RangeBar({
  const deltaText =
    delta > 0
      ? value < min
-        ? t("targets.belowTarget", { delta: delta.toFixed(1), unit })
-        : t("targets.aboveTarget", { delta: delta.toFixed(1), unit })
+        ? t("targets.belowTarget", { delta: fmt.number(delta, 1), unit })
+        : t("targets.aboveTarget", { delta: fmt.number(delta, 1), unit })
      : t("targets.inTarget");

  // 2026-07-17 a11y audit (M1) — the marker's value + range live only in a
@@ -142,8 +153,8 @@ export function RangeBar({
  // 1.1.1 (no separate copy to drift) — `tabIndex` below makes the trigger
  // focusable, which is all Radix needs to also open the tooltip on focus.
  const markerAriaLabel = [
-    t("targets.currentValue", { value: String(value), unit }),
-    t("targets.targetRangeValue", { min: String(min), max: String(max), unit }),
+    t("targets.currentValue", { value: show(value), unit }),
+    t("targets.targetRangeValue", { min: show(min), max: show(max), unit }),
    deltaText,
  ].join(". ");

@@ -218,12 +229,12 @@ export function RangeBar({
            </TooltipTrigger>
            <TooltipContent>
              <p className="text-xs font-medium">
-                {t("targets.currentValue", { value: String(value), unit })}
+                {t("targets.currentValue", { value: show(value), unit })}
              </p>
              <p className="text-xs">
                {t("targets.targetRangeValue", {
-                  min: String(min),
-                  max: String(max),
+                  min: show(min),
+                  max: show(max),
                  unit,
                })}
              </p>
@@ -241,13 +252,13 @@ export function RangeBar({
          className="absolute -translate-x-1/2 whitespace-nowrap"
          style={{ left: `${minLabelPosition}%` }}
        >
-          {minLabel === null ? null : (minLabel ?? `${min} ${unit}`)}
+          {minLabel === null ? null : (minLabel ?? `${show(min)} ${unit}`)}
        </span>
        <span
          className="absolute -translate-x-1/2 whitespace-nowrap"
          style={{ left: `${maxLabelPosition}%` }}
        >
-          {maxLabel === null ? null : (maxLabel ?? `${max} ${unit}`)}
+          {maxLabel === null ? null : (maxLabel ?? `${show(max)} ${unit}`)}
        </span>
      </div>
    </div>
@@ -93,6 +93,19 @@ describe("<DateField>", () => {
    expect(html).toContain("sm:h-10");
  });

+  it("gives the calendar button a 44 px touch target at its 32 px size", () => {
+    const html = render(<DateField value="2026-02-19" />);
+    const button = /<button[^>]*aria-label="Open date picker"[^>]*>/.exec(
+      html,
+    )?.[0];
+    expect(button).toBeDefined();
+    // Painted size unchanged; the ::before halo adds 6 px per edge.
+    expect(button).toContain("h-8 w-8");
+    expect(button).toContain("relative");
+    expect(button).toContain("before:-inset-1.5");
+    expect(button).toContain("before:absolute");
+  });
+
  it("exposes a labelled calendar picker affordance", () => {
    const html = render(<DateField value="2026-02-19" />);
    expect(html).toContain('aria-label="Open date picker"');
@@ -105,6 +105,18 @@ describe("formatHhmm", () => {
 });

 describe("<TimeField> SSR", () => {
+  it("gives the clock button a 44 px touch target at its 32 px size", () => {
+    const html = render(<TimeField value="14:05" />, "de");
+    const button = /<button[^>]*data-slot="time-field-trigger"[^>]*>/.exec(
+      html,
+    )?.[0];
+    expect(button).toBeDefined();
+    expect(button).toContain("h-8 w-8");
+    expect(button).toContain("relative");
+    expect(button).toContain("before:-inset-1.5");
+    expect(button).toContain("before:absolute");
+  });
+
  it("paints the value in 24h under the de AUTO locale and exposes the picker affordance", () => {
    const html = render(<TimeField value="14:05" />, "de");
    expect(html).toContain('value="14:05"');
@@ -225,7 +225,9 @@ export const DateField = React.forwardRef<HTMLInputElement, DateFieldProps>(
              type="button"
              disabled={disabled}
              aria-label={t("common.openDatePicker")}
-              className="text-muted-foreground hover:text-foreground flex h-8 w-8 shrink-0 items-center justify-center rounded-md disabled:cursor-not-allowed disabled:opacity-50"
+              // The button paints at 32 px; the `::before` halo (6 px per edge)
+              // makes the touch target 44 px without changing the field.
+              className="text-muted-foreground hover:text-foreground relative flex h-8 w-8 shrink-0 items-center justify-center rounded-md before:absolute before:-inset-1.5 before:content-[''] disabled:cursor-not-allowed disabled:opacity-50"
            >
              <CalendarIcon className="h-4 w-4" aria-hidden="true" />
            </button>
@@ -189,7 +189,9 @@ export const TimeField = React.forwardRef<HTMLInputElement, TimeFieldProps>(
              tabIndex={-1}
              disabled={disabled}
              aria-label={t("common.openTimePicker")}
-              className="text-muted-foreground hover:text-foreground flex h-8 w-8 shrink-0 items-center justify-center rounded-md disabled:cursor-not-allowed disabled:opacity-50"
+              // The button paints at 32 px; the `::before` halo (6 px per edge)
+              // makes the touch target 44 px without changing the field.
+              className="text-muted-foreground hover:text-foreground relative flex h-8 w-8 shrink-0 items-center justify-center rounded-md before:absolute before:-inset-1.5 before:content-[''] disabled:cursor-not-allowed disabled:opacity-50"
              data-slot="time-field-trigger"
            >
              <Clock className="h-4 w-4" aria-hidden="true" />
@@ -0,0 +1,32 @@
+"use client";
+
+import { useCallback } from "react";
+
+import { formatDate } from "@/lib/date-format";
+import { useDateFormatPreference, useTranslations } from "@/lib/i18n/context";
+
+/**
+ * Format a date-only value: a `YYYY-MM-DD` key, or a stored instant that
+ * stands for a calendar date (noon UTC, or a `@db.Date` column's UTC
+ * midnight). The calendar date is read in UTC, so it is the same day in
+ * every zone.
+ *
+ * Formatting such a value in the reader's zone is how a noon-UTC date came
+ * to show the next day from UTC+12 to UTC+14. Same field order and locale as
+ * `useFormatters().date`, so it sits beside instant-formatted dates without
+ * looking different.
+ */
+export function useCalendarDate(): (value: string | Date) => string {
+  const { locale } = useTranslations();
+  const dateFormat = useDateFormatPreference();
+  return useCallback(
+    (value: string | Date) =>
+      formatDate(
+        // `formatDate` reads a bare key as a calendar date already.
+        typeof value === "string" ? value.slice(0, 10) : value,
+        dateFormat,
+        locale,
+      ),
+    [dateFormat, locale],
+  );
+}
@@ -594,6 +594,30 @@ describe("doctor-report clinical glucose panel", () => {
    expect(text).toContain("Glucose Management Indicator");
  });

+  it("labels the time-in-range bands in the owner's glucose unit", async () => {
+    // The band labels used to read "Low (< 70 mg/dL)" in a report whose
+    // values were all in mmol/L.
+    const data = makeData({
+      glucoseUnit: "mmol/L",
+      glucoseClinical: computeGlucoseClinicalMetrics(denseReadings(), {
+        now: FIXED_NOW,
+        windowDays: 90,
+      }),
+    });
+    const bytes = renderDoctorReportPdfBytes(data, {
+      timeFormat: "AUTO",
+      dateFormat: "AUTO",
+      t: getServerTranslator("de").t,
+      locale: "de",
+      now: FIXED_NOW,
+    });
+    const text = await extractText(bytes);
+    expect(text).toContain("Zeit im Zielbereich (3,9–10,0 mmol/L)");
+    expect(text).toContain("Sehr niedrig (< 3,0 mmol/L)");
+    expect(text).toContain("Sehr hoch (> 13,9 mmol/L)");
+    expect(text).not.toMatch(/mg\/dl/i);
+  });
+
  it("omits the clinical panel when there are no glucose readings", async () => {
    const data = makeData(); // empty (zero-reading) glucose panel
    const bytes = renderDoctorReportPdfBytes(data, {
@@ -9,7 +9,11 @@ import {
  glucoseContextBucket,
  groupByGlucoseContext,
  GLUCOSE_CONTEXT_UNSPECIFIED,
+  GLUCOSE_FASTING_CUT_POINTS,
+  GLUCOSE_TIR_CUT_POINTS,
+  glucoseBandParams,
 } from "../glucose";
+import { makeFormatters } from "../format-locale";

 describe("glucose conversion", () => {
  it("converts mg/dL to mmol/L with 1 decimal", () => {
@@ -157,3 +161,45 @@ describe("glucose context buckets (#943)", () => {
    );
  });
 });
+
+describe("glucose band parameters", () => {
+  const de = makeFormatters("de", "UTC", "AUTO", "AUTO").number;
+  const en = makeFormatters("en", "UTC", "AUTO", "AUTO").number;
+
+  it("states the consensus bands in mg/dL as whole numbers", () => {
+    expect(glucoseBandParams("mg/dL", en)).toMatchObject({
+      unit: "mg/dL",
+      veryLow: "54",
+      low: "70",
+      high: "180",
+      veryHigh: "250",
+      prediabetesFrom: "100",
+      prediabetesTo: "125",
+      diabetesFrom: "126",
+    });
+  });
+
+  it("states them in mmol/L with the locale's decimal separator", () => {
+    expect(glucoseBandParams("mmol/L", de)).toMatchObject({
+      unit: "mmol/L",
+      veryLow: "3,0",
+      low: "3,9",
+      high: "10,0",
+      veryHigh: "13,9",
+      prediabetesFrom: "5,6",
+      prediabetesTo: "6,9",
+      diabetesFrom: "7,0",
+    });
+  });
+
+  it("carries SI figures that agree with the conversion", () => {
+    // The consensus bands convert exactly; the ADA cut-points are within
+    // one rounding step of it (100 mg/dL is printed as 5.6, converts to 5.5).
+    for (const point of Object.values(GLUCOSE_TIR_CUT_POINTS)) {
+      expect(point.mmol).toBe(mgdlToMmol(point.mgdl));
+    }
+    for (const point of Object.values(GLUCOSE_FASTING_CUT_POINTS)) {
+      expect(Math.abs(point.mmol - point.mgdl / 18.0182)).toBeLessThan(0.1);
+    }
+  });
+});
@@ -39,6 +39,8 @@
 *     Diabetes Care 29(11):2433-2438, DOI 10.2337/dc06-1085.
 */

+import { GLUCOSE_TIR_CUT_POINTS } from "@/lib/glucose";
+
 // ── Inputs ───────────────────────────────────────────────

 /** A single spot blood-glucose reading. Value is canonical mg/dL. */
@@ -79,11 +81,13 @@ export interface GlucoseMetricsOptions {
 }

 // ── Consensus thresholds (Battelino 2019) ────────────────
-// Bands in mg/dL. These are consensus FACTS, cited above.
-const TBR_LEVEL2_MAX = 54; // very low: G < 54
-const TBR_LEVEL1_MAX = 70; // low: G < 70 (level-1 sub-band is 54–69)
-const TAR_LEVEL1_MIN = 180; // high: G > 180 (level-1 sub-band is 181–250)
-const TAR_LEVEL2_MIN = 250; // very high: G > 250
+// Bands in mg/dL. These are consensus FACTS, cited above. The values live in
+// `GLUCOSE_TIR_CUT_POINTS` so the band labels a reader sees and the bands
+// this engine counts are the same numbers.
+const TBR_LEVEL2_MAX = GLUCOSE_TIR_CUT_POINTS.veryLow.mgdl; // very low: G < 54
+const TBR_LEVEL1_MAX = GLUCOSE_TIR_CUT_POINTS.low.mgdl; // low: G < 70 (level-1 sub-band is 54–69)
+const TAR_LEVEL1_MIN = GLUCOSE_TIR_CUT_POINTS.high.mgdl; // high: G > 180 (level-1 sub-band is 181–250)
+const TAR_LEVEL2_MIN = GLUCOSE_TIR_CUT_POINTS.veryHigh.mgdl; // very high: G > 250
 // Time-in-range target band is [70, 180] inclusive.
 /** The time-in-range band, mg/dL, inclusive at both ends. */
 export const TIME_IN_RANGE_MGDL = {
@@ -0,0 +1,56 @@
+import { readFileSync } from "node:fs";
+import { join } from "node:path";
+
+import { describe, expect, it } from "vitest";
+
+import {
+  stripComments,
+  walkSourceFiles,
+} from "@/__tests__/helpers/source-files";
+import { axisUnitSuffix } from "../axis-unit";
+
+const COMPONENTS = join(process.cwd(), "src", "components");
+
+/**
+ * Every `<XAxis … />` / `<YAxis … />` tag's `unit=` value in the tree. The tag
+ * runs to its `/>`: stopping at the first `>` would end it inside an arrow
+ * function prop and miss a `unit` written after one.
+ */
+function axisUnitProps(): Array<{ file: string; value: string }> {
+  const out: Array<{ file: string; value: string }> = [];
+  for (const rel of walkSourceFiles(COMPONENTS, {
+    floor: 300,
+    extensions: [".tsx"],
+  })) {
+    if (rel.includes("__tests__")) continue;
+    const src = stripComments(readFileSync(join(COMPONENTS, rel), "utf8"));
+    for (const tag of src.matchAll(/<[XY]Axis\b[\s\S]*?\/>/g)) {
+      const unit = /\bunit=(\{[\s\S]*?\}|"[^"]*")/.exec(tag[0]);
+      if (unit) out.push({ file: rel, value: unit[1] });
+    }
+  }
+  return out;
+}
+
+describe("axis unit suffix", () => {
+  it("joins the unit with a no-break space", () => {
+    expect(axisUnitSuffix("bpm")).toBe(" bpm");
+    expect(axisUnitSuffix("")).toBeUndefined();
+    expect(axisUnitSuffix(null)).toBeUndefined();
+  });
+
+  it("finds the axis units it is meant to police", () => {
+    // A matcher that finds nothing would pass the check below by default.
+    expect(axisUnitProps().length).toBeGreaterThanOrEqual(6);
+  });
+
+  it("no chart axis joins a unit with a breaking space", () => {
+    // Recharts wraps a tick label at a breaking space when it measures the
+    // label wider than the axis, and it measures in the body font: "62 bpm"
+    // broke onto two lines and its second line sat on the first x tick.
+    const offenders = axisUnitProps()
+      .filter(({ value }) => /["`] /.test(value))
+      .map(({ file, value }) => `${file}: unit=${value}`);
+    expect(offenders).toEqual([]);
+  });
+});
@@ -0,0 +1,15 @@
+/**
+ * The unit suffix a chart axis appends to each tick value ("62 bpm").
+ *
+ * Joined with a no-break space, never a plain one. Recharts word-wraps a
+ * tick label that is wider than the axis, and it measures the label in the
+ * page's body font rather than the tick's own 11 px, so "62 bpm" and
+ * "106 mg/dL" measured wider than their axis and broke onto two lines on
+ * every screen. The second line dropped onto the first x tick. A label with
+ * no breaking space is one word and stays on one line.
+ */
+export function axisUnitSuffix(
+  unit: string | null | undefined,
+): string | undefined {
+  return unit ? ` ${unit}` : undefined;
+}
@@ -1,7 +1,11 @@
 import type { jsPDF } from "jspdf";
 import { GLUCOSE_CONTEXT_BUCKETS } from "@/lib/glucose";
 import autoTable from "jspdf-autotable";
-import { convertGlucose, resolveGlucoseUnit } from "../glucose";
+import {
+  convertGlucose,
+  glucoseBandParams,
+  resolveGlucoseUnit,
+} from "../glucose";
 import { reportStatValue } from "../doctor-report/stat-display";
 import type { MeasurementType } from "@/generated/prisma/client";
 import { MEASUREMENT_TYPE_LABEL_KEYS } from "../measurements/type-label-keys";
@@ -303,26 +307,29 @@ export function buildMeasurementsChartsSection(
  const clinical = data.glucoseClinical;
  if (clinical && clinical.readingCount > 0 && clinical.distribution) {
    const pct = (fraction: number) => `${num(fraction * 100)} %`;
+    // The band edges follow the reader's glucose unit, like every value in
+    // the table beside them.
+    const bands = glucoseBandParams(glucoseUnit, num);
    const clinicalRows: string[][] = [];
    const dist = clinical.distribution;
    clinicalRows.push([
-      t("doctorReport.glucoseClinical.tirInRange"),
+      t("doctorReport.glucoseClinical.tirInRange", bands),
      pct(dist.tir),
    ]);
    clinicalRows.push([
-      t("doctorReport.glucoseClinical.tirLow"),
+      t("doctorReport.glucoseClinical.tirLow", bands),
      pct(dist.tbrLevel1),
    ]);
    clinicalRows.push([
-      t("doctorReport.glucoseClinical.tirVeryLow"),
+      t("doctorReport.glucoseClinical.tirVeryLow", bands),
      pct(dist.tbrLevel2),
    ]);
    clinicalRows.push([
-      t("doctorReport.glucoseClinical.tirHigh"),
+      t("doctorReport.glucoseClinical.tirHigh", bands),
      pct(dist.tarLevel1),
    ]);
    clinicalRows.push([
-      t("doctorReport.glucoseClinical.tirVeryHigh"),
+      t("doctorReport.glucoseClinical.tirVeryHigh", bands),
      pct(dist.tarLevel2),
    ]);
    if (clinical.meanMgdl !== null) {
@@ -42,6 +42,59 @@ export function toCanonicalMgdl(value: number, from: GlucoseUnit): number {
  return from === "mmol/L" ? mmolToMgdl(value) : Math.round(value);
 }

+/**
+ * A published glucose cut-point, in both units as its source states it.
+ *
+ * The SI figure is carried rather than converted because a guideline prints
+ * its own rounding: ADA's fasting cut-point is 100 mg/dL and 5.6 mmol/L, and
+ * `mgdlToMmol(100)` gives 5.5. A reader on mmol/L must see the number their
+ * own guideline prints, not a re-rounded neighbour of it.
+ */
+export interface GlucoseCutPoint {
+  mgdl: number;
+  mmol: number;
+}
+
+/** Consensus time-in-range band edges (Battelino 2019). */
+export const GLUCOSE_TIR_CUT_POINTS = {
+  veryLow: { mgdl: 54, mmol: 3.0 },
+  low: { mgdl: 70, mmol: 3.9 },
+  high: { mgdl: 180, mmol: 10.0 },
+  veryHigh: { mgdl: 250, mmol: 13.9 },
+} as const satisfies Record<string, GlucoseCutPoint>;
+
+/** Fasting-glucose diagnostic cut-points for adults (ADA 2024). */
+export const GLUCOSE_FASTING_CUT_POINTS = {
+  prediabetesFrom: { mgdl: 100, mmol: 5.6 },
+  prediabetesTo: { mgdl: 125, mmol: 6.9 },
+  diabetesFrom: { mgdl: 126, mmol: 7.0 },
+} as const satisfies Record<string, GlucoseCutPoint>;
+
+/**
+ * The interpolation parameters every glucose band sentence takes: each
+ * cut-point in the reader's unit, formatted by the caller's locale-aware
+ * number formatter, plus the unit symbol. A sentence that names a band
+ * reads its numbers from here, so no locale string carries a fixed unit.
+ */
+export function glucoseBandParams(
+  unit: GlucoseUnit,
+  formatNumber: (value: number, fractionDigits: number) => string,
+): Record<string, string> {
+  const digits = unit === "mmol/L" ? 1 : 0;
+  const v = (point: GlucoseCutPoint) =>
+    formatNumber(unit === "mmol/L" ? point.mmol : point.mgdl, digits);
+  return {
+    unit,
+    veryLow: v(GLUCOSE_TIR_CUT_POINTS.veryLow),
+    low: v(GLUCOSE_TIR_CUT_POINTS.low),
+    high: v(GLUCOSE_TIR_CUT_POINTS.high),
+    veryHigh: v(GLUCOSE_TIR_CUT_POINTS.veryHigh),
+    prediabetesFrom: v(GLUCOSE_FASTING_CUT_POINTS.prediabetesFrom),
+    prediabetesTo: v(GLUCOSE_FASTING_CUT_POINTS.prediabetesTo),
+    diabetesFrom: v(GLUCOSE_FASTING_CUT_POINTS.diabetesFrom),
+  };
+}
+
 export function resolveGlucoseUnit(
  userPreference: string | null | undefined,
 ): GlucoseUnit {
@@ -0,0 +1,25 @@
+import { describe, expect, it } from "vitest";
+
+import { makeFormatters } from "@/lib/format-locale";
+import { formatLabReading, formatLabValue } from "../format-value";
+
+const de = (n: number) => makeFormatters("de", "UTC", "AUTO", "AUTO").number(n);
+const en = (n: number) => makeFormatters("en", "UTC", "AUTO", "AUTO").number(n);
+
+describe("lab value formatting", () => {
+  it("trims to two decimals and prints the locale's separator", () => {
+    expect(formatLabValue(1.8, de)).toBe("1,8");
+    expect(formatLabValue(1.8, en)).toBe("1.8");
+    expect(formatLabValue(0.123456, de)).toBe("0,12");
+    expect(formatLabValue(5, de)).toBe("5");
+  });
+
+  it("formats a numeric reading with its unit and leaves a qualitative one verbatim", () => {
+    expect(
+      formatLabReading({ value: 61.3, valueText: null, unit: "kg" }, de),
+    ).toBe("61,3 kg");
+    expect(
+      formatLabReading({ value: null, valueText: "negativ", unit: "" }, de),
+    ).toBe("negativ");
+  });
+});
@@ -5,11 +5,20 @@
 * lab reading the same way: whole numbers render bare, fractional values keep
 * up to two decimals (no trailing-zero noise). Centralised so the three
 * surfaces stay byte-identical.
+ *
+ * The digits themselves come from the caller's locale number formatter
+ * (`useFormatters().number`), so a German reader sees "1,8 mIU/L" where an
+ * English one sees "1.8 mIU/L". This module only decides the precision.
 */
-export function formatLabValue(value: number): string {
-  return Number.isInteger(value)
-    ? String(value)
-    : String(Number(value.toFixed(2)));
+export type LabNumberFormat = (value: number) => string;
+
+export function formatLabValue(
+  value: number,
+  formatNumber: LabNumberFormat,
+): string {
+  return formatNumber(
+    Number.isInteger(value) ? value : Number(value.toFixed(2)),
+  );
 }

 /**
@@ -18,13 +27,16 @@ export function formatLabValue(value: number): string {
 * formatted number plus its unit. One helper so the list card, the history
 * rows, and the detail header stay consistent.
 */
-export function formatLabReading(reading: {
-  value: number | null;
-  valueText: string | null;
-  unit: string;
-}): string {
+export function formatLabReading(
+  reading: {
+    value: number | null;
+    valueText: string | null;
+    unit: string;
+  },
+  formatNumber: LabNumberFormat,
+): string {
  if (reading.value === null) {
    return reading.valueText ?? "";
  }
-  return `${formatLabValue(reading.value)} ${reading.unit}`.trim();
+  return `${formatLabValue(reading.value, formatNumber)} ${reading.unit}`.trim();
 }
@@ -1,5 +1,6 @@
 import { describe, expect, it } from "vitest";
 import {
+  isNoonUtcAnchor,
  dateOnlyAtNoonUtc,
  dateOnlyKey,
  dayKeyAsUtcMidnight,
@@ -50,3 +51,12 @@ describe("calendar key arithmetic", () => {
    expect(weekdayOfDateKey("2026-10-04")).toBe(0); // Sunday
  });
 });
+
+describe("isNoonUtcAnchor", () => {
+  it("recognises the stored anchor of a date-only value and nothing else", () => {
+    expect(isNoonUtcAnchor(dateOnlyAtNoonUtc("2025-10-04"))).toBe(true);
+    expect(isNoonUtcAnchor(new Date("2025-10-04T12:00:01.000Z"))).toBe(false);
+    expect(isNoonUtcAnchor(new Date("2025-10-04T00:00:00.000Z"))).toBe(false);
+    expect(isNoonUtcAnchor(new Date("2025-10-04T20:30:00.000Z"))).toBe(false);
+  });
+});
@@ -58,6 +58,24 @@ export function dateOnlyAtNoonUtc(key: string): Date {
  return new Date(`${key}T12:00:00.000Z`);
 }

+/**
+ * True when a stored instant is the noon-UTC anchor of a date-only value.
+ *
+ * For a column that holds both kinds (a lab reading typed with its time of
+ * day, or imported from a report that states only the date), this is how a
+ * reader tells them apart. A reading typed at exactly 12:00:00.000 UTC reads
+ * as its UTC calendar date, which is its local date everywhere from UTC-11
+ * to UTC+11.
+ */
+export function isNoonUtcAnchor(value: Date): boolean {
+  return (
+    value.getUTCHours() === 12 &&
+    value.getUTCMinutes() === 0 &&
+    value.getUTCSeconds() === 0 &&
+    value.getUTCMilliseconds() === 0
+  );
+}
+
 /**
 * The calendar date of a stored date-only value (or of a `@db.Date` column,
 * which Prisma hands back as UTC midnight). Only for values that ARE dates: