feat(labs): show a reading's conversion in the scan review and beside the value

Slice 3 of phase 3 of #1095. The scan review no longer treats every reading in
another unit as unwritable. The server tells it which analyte the matched marker
is (markerAnalyteKey on each extracted row); a row whose unit differs but can be
converted starts selected and carries a badge saying what Save will store and
what the report stated ("Saved as 100.9 mg/dL, converted from 5.6 mmol/L"). A
row that cannot be converted keeps the existing blocked badge and error. Save
still sends what the report printed; the server converts, as in slice 2.

The review's duplicate flag also recognises a re-scan of a reading that was
stored converted, by what the report printed, the same rule the commit applies.

A converted reading carries a quiet "converted from 5.6 mmol/L" on the lab list
(row and tile) and the history list (phone and table), so a number nobody typed
can always be traced back to what the report printed.

Strings in all seven locales.

Refs #1095

docs/api/openapi.yaml

@@ -68232,8 +68232,16 @@ components:
             - type: string
             - type: "null"
           description: "The unit the matched marker is tracked in, or null when the marker does not exist yet (it will adopt this
-            row's unit). A row whose `unit` differs from it cannot be committed: the commit skips it with `reason:
-            unit_mismatch`, and the review screen marks it before Save."
+            row's unit). A row whose `unit` differs from it is converted on commit when the marker's analyte is known
+            and the pair is in the unit-conversion registry; otherwise the commit skips it with `reason: unit_mismatch`,
+            and the review screen marks it before Save."
+        markerAnalyteKey:
+          anyOf:
+            - type: string
+            - type: "null"
+          description: The analyte the matched marker is (the unit-conversion registry's key, e.g. `fasting-glucose`), or null
+            when the marker does not exist yet or its name matches none. With `markerUnit` it tells a client whether a
+            row in another unit can be converted on commit.
         duplicateOf:
           anyOf:
             - type: string
@@ -68250,6 +68258,7 @@ components:
         - confidence
         - biomarkerMatch
         - markerUnit
+        - markerAnalyteKey
         - duplicateOf
       additionalProperties: false
       description: "One proposed reading transcribed from the upload. UNTRUSTED model output annotated server-side:

messages/de.json

@@ -9522,6 +9522,7 @@
     },
     "noteLoadFailed": "Notiz konnte nicht geladen werden; sie bleibt beim Speichern unverändert.",
     "showingLatestOf": "Die neuesten {shown} von {total} Messwerten werden angezeigt",
+    "convertedFrom": "umgerechnet aus {value} {unit}",
     "ocr": {
       "scanButton": "Befund scannen",
       "addScan": "Dokument scannen",
@@ -9568,6 +9569,7 @@
       "errorUnit": "Bitte eine Einheit angeben.",
       "errorUnitMismatch": "Dieser Marker wird in {markerUnit} geführt. Ändere die Einheit, falls der Befund falsch gelesen wurde, oder wähle den Wert ab.",
       "unitDiffersBadge": "Geführt in {markerUnit}; dieser Befund nennt {unit}",
+      "unitConvertedBadge": "Wird als {value} {markerUnit} gespeichert, umgerechnet aus {statedValue} {unit}",
       "savedPartialUnitToast": "{count} Laborwerte gespeichert. Nicht gespeichert, weil die Einheit von der des Markers abweicht: {analytes}",
       "savedNothingUnitToast": "Nichts gespeichert: Die Einheit weicht bei {analytes} von der des Markers ab",
       "saveFailed": "Werte konnten nicht gespeichert werden. Bitte erneut versuchen.",

messages/en.json

@@ -9522,6 +9522,7 @@
     },
     "noteLoadFailed": "Note could not be loaded; it will be kept unchanged when you save.",
     "showingLatestOf": "Showing the latest {shown} of {total} readings",
+    "convertedFrom": "converted from {value} {unit}",
     "ocr": {
       "scanButton": "Scan a report",
       "addScan": "Scan a document",
@@ -9568,6 +9569,7 @@
       "errorUnit": "Add a unit.",
       "errorUnitMismatch": "This marker is tracked in {markerUnit}. Change the unit if the report was misread, or deselect this reading.",
       "unitDiffersBadge": "Tracked in {markerUnit}; this report says {unit}",
+      "unitConvertedBadge": "Saved as {value} {markerUnit}, converted from {statedValue} {unit}",
       "savedPartialUnitToast": "{count} lab results saved. Not saved, because the unit differs from the marker's: {analytes}",
       "savedNothingUnitToast": "Nothing saved: the unit differs from the marker's for {analytes}",
       "saveFailed": "Couldn't save the readings. Please try again.",

messages/es.json

@@ -9522,6 +9522,7 @@
     },
     "noteLoadFailed": "No se pudo cargar la nota; se mantendrá sin cambios al guardar.",
     "showingLatestOf": "Mostrando los {shown} resultados más recientes de {total}",
+    "convertedFrom": "convertido desde {value} {unit}",
     "ocr": {
       "scanButton": "Escanear un informe",
       "addScan": "Escanear un documento",
@@ -9568,6 +9569,7 @@
       "errorUnit": "Añade una unidad.",
       "errorUnitMismatch": "Este marcador se registra en {markerUnit}. Cambia la unidad si el informe se leyó mal o deselecciona este valor.",
       "unitDiffersBadge": "Registrado en {markerUnit}; este informe indica {unit}",
+      "unitConvertedBadge": "Se guardará como {value} {markerUnit}, convertido desde {statedValue} {unit}",
       "savedPartialUnitToast": "{count} resultados guardados. No guardados porque la unidad difiere de la del marcador: {analytes}",
       "savedNothingUnitToast": "No se guardó nada: la unidad difiere de la del marcador en {analytes}",
       "saveFailed": "No se pudieron guardar los valores. Inténtalo de nuevo.",

messages/fr.json

@@ -9522,6 +9522,7 @@
     },
     "noteLoadFailed": "La note n’a pas pu être chargée ; elle restera inchangée à l’enregistrement.",
     "showingLatestOf": "Affichage des {shown} derniers résultats sur {total}",
+    "convertedFrom": "converti depuis {value} {unit}",
     "ocr": {
       "scanButton": "Scanner un compte rendu",
       "addScan": "Scanner un document",
@@ -9568,6 +9569,7 @@
       "errorUnit": "Indiquez une unité.",
       "errorUnitMismatch": "Ce marqueur est suivi en {markerUnit}. Modifiez l’unité si le compte rendu a été mal lu, ou désélectionnez cette valeur.",
       "unitDiffersBadge": "Suivi en {markerUnit} ; ce compte rendu indique {unit}",
+      "unitConvertedBadge": "Enregistré comme {value} {markerUnit}, converti depuis {statedValue} {unit}",
       "savedPartialUnitToast": "{count} résultats enregistrés. Non enregistrés, car l’unité diffère de celle du marqueur : {analytes}",
       "savedNothingUnitToast": "Rien n’a été enregistré : l’unité diffère de celle du marqueur pour {analytes}",
       "saveFailed": "Impossible d'enregistrer les valeurs. Veuillez réessayer.",

messages/it.json

@@ -9522,6 +9522,7 @@
     },
     "noteLoadFailed": "Impossibile caricare la nota; resterà invariata al salvataggio.",
     "showingLatestOf": "Visualizzazione degli ultimi {shown} risultati su {total}",
+    "convertedFrom": "convertito da {value} {unit}",
     "ocr": {
       "scanButton": "Scansiona un referto",
       "addScan": "Scansiona un documento",
@@ -9568,6 +9569,7 @@
       "errorUnit": "Inserisci un'unità.",
       "errorUnitMismatch": "Questo marcatore è registrato in {markerUnit}. Cambia l’unità se il referto è stato letto male, oppure deseleziona questo valore.",
       "unitDiffersBadge": "Registrato in {markerUnit}; questo referto indica {unit}",
+      "unitConvertedBadge": "Verrà salvato come {value} {markerUnit}, convertito da {statedValue} {unit}",
       "savedPartialUnitToast": "{count} risultati salvati. Non salvati perché l’unità è diversa da quella del marcatore: {analytes}",
       "savedNothingUnitToast": "Nulla salvato: l’unità è diversa da quella del marcatore per {analytes}",
       "saveFailed": "Impossibile salvare i valori. Riprova.",

messages/ko.json

@@ -9522,6 +9522,7 @@
     },
     "noteLoadFailed": "메모를 불러오지 못했어요. 저장해도 메모는 그대로 유지돼요.",
     "showingLatestOf": "측정값 {total}개 중 최근 {shown}개를 보여주고 있어요",
+    "convertedFrom": "{value} {unit}에서 변환됨",
     "ocr": {
       "scanButton": "결과지 스캔",
       "addScan": "문서 스캔",
@@ -9568,6 +9569,7 @@
       "errorUnit": "단위를 입력하세요.",
       "errorUnitMismatch": "이 지표는 {markerUnit} 단위로 기록됩니다. 결과지를 잘못 읽었다면 단위를 바꾸거나 이 값의 선택을 해제하세요.",
       "unitDiffersBadge": "{markerUnit} 단위로 기록 중; 이 결과지는 {unit}",
+      "unitConvertedBadge": "{value} {markerUnit}(으)로 저장됩니다. {statedValue} {unit}에서 변환됨",
       "savedPartialUnitToast": "검사 결과 {count}개를 저장했습니다. 단위가 지표와 달라 저장하지 않은 항목: {analytes}",
       "savedNothingUnitToast": "저장된 항목이 없습니다: {analytes}의 단위가 지표와 다릅니다",
       "saveFailed": "측정값을 저장하지 못했어요. 다시 시도해 주세요.",

messages/pl.json

@@ -9522,6 +9522,7 @@
     },
     "noteLoadFailed": "Nie udało się wczytać notatki; pozostanie niezmieniona po zapisaniu.",
     "showingLatestOf": "Wyświetlanie najnowszych {shown} z {total} wyników",
+    "convertedFrom": "przeliczono z {value} {unit}",
     "ocr": {
       "scanButton": "Zeskanuj wynik",
       "addScan": "Zeskanuj dokument",
@@ -9568,6 +9569,7 @@
       "errorUnit": "Podaj jednostkę.",
       "errorUnitMismatch": "Ten wskaźnik jest prowadzony w {markerUnit}. Zmień jednostkę, jeśli wynik został źle odczytany, albo odznacz tę wartość.",
       "unitDiffersBadge": "Prowadzony w {markerUnit}; ten wynik podaje {unit}",
+      "unitConvertedBadge": "Zostanie zapisane jako {value} {markerUnit}, przeliczone z {statedValue} {unit}",
       "savedPartialUnitToast": "Zapisano {count} wyników. Nie zapisano, bo jednostka różni się od jednostki wskaźnika: {analytes}",
       "savedNothingUnitToast": "Nic nie zapisano: jednostka różni się od jednostki wskaźnika dla {analytes}",
       "saveFailed": "Nie udało się zapisać wyników. Spróbuj ponownie.",

src/components/labs/__tests__/lab-converted-note.test.tsx

@@ -0,0 +1,49 @@
+import { renderToStaticMarkup } from "react-dom/server";
+import { describe, expect, it } from "vitest";
+
+import { I18nProvider } from "@/lib/i18n/context";
+
+import { LabConvertedNote } from "../lab-converted-note";
+
+function render(
+  reading: Parameters<typeof LabConvertedNote>[0]["reading"],
+  locale: "en" | "de" = "en",
+) {
+  return renderToStaticMarkup(
+    <I18nProvider initialLocale={locale}>
+      <LabConvertedNote reading={reading} />
+    </I18nProvider>,
+  );
+}
+
+describe("<LabConvertedNote>", () => {
+  it("says what the report printed beside a converted reading", () => {
+    const html = render({
+      converted: true,
+      sourceValue: 5.6,
+      sourceUnit: "mmol/L",
+    });
+    expect(html).toContain('data-slot="lab-converted-note"');
+    expect(html).toContain("converted from 5.6 mmol/L");
+  });
+
+  it("formats the number for the reader's language", () => {
+    expect(
+      render({ converted: true, sourceValue: 5.6, sourceUnit: "mmol/L" }, "de"),
+    ).toContain("umgerechnet aus 5,6 mmol/L");
+  });
+
+  it("trims a long fraction the way the reading itself is trimmed", () => {
+    expect(
+      render({ converted: true, sourceValue: 5.6123456, sourceUnit: "mmol/L" }),
+    ).toContain("converted from 5.61 mmol/L");
+  });
+
+  it.each([
+    [{ converted: false, sourceValue: null, sourceUnit: null }],
+    [{ converted: true, sourceValue: null, sourceUnit: "mmol/L" }],
+    [{ converted: true, sourceValue: 5.6, sourceUnit: null }],
+  ])("renders nothing for %j", (reading) => {
+    expect(render(reading)).toBe("");
+  });
+});

src/components/labs/__tests__/lab-list-columns.test.tsx

@@ -29,6 +29,9 @@ function reading(over: Partial<LabResultDto>): LabResultDto {
     value: 80,
     valueText: null,
     unit: "ng/mL",
+    converted: false,
+    sourceValue: null,
+    sourceUnit: null,
     referenceLow: 30,
     referenceHigh: 400,
     catalogReferenceLow: 30,
@@ -165,4 +168,21 @@ describe("<LabList> columns", () => {
       }
     });
   });
+
+  it("notes where a converted reading came from, and only for that reading", () => {
+    const html = renderList([
+      reading({
+        id: "c",
+        biomarkerId: "b1",
+        analyte: "Glucose",
+        unit: "mg/dL",
+        converted: true,
+        sourceValue: 5.6,
+        sourceUnit: "mmol/L",
+      }),
+      reading({ id: "d", biomarkerId: "b2", analyte: "Ferritin" }),
+    ]);
+    expect(count(html, 'data-slot="lab-converted-note"')).toBe(1);
+    expect(html).toContain("converted from 5.6 mmol/L");
+  });
 });

src/components/labs/__tests__/ocr-review-validation.test.ts

@@ -5,6 +5,8 @@ import { seedReviewRows } from "../ocr-review-types";
 import {
   collectRowErrors,
   planSave,
+  readingConversion,
+  readingUnitBlocked,
   readingUnitDiffers,
   toCommitRow,
   validateReviewRow,
@@ -24,6 +26,7 @@ function row(overrides: Partial<OcrReviewRow> = {}): OcrReviewRow {
     confidence: { analyte: 1, value: 1, unit: 1, range: 1 },
     biomarkerMatch: "existing",
     markerUnit: "mmol/L",
+    markerAnalyteKey: null,
     duplicateOf: null,
     confirmed: true,
     ...overrides,
@@ -200,6 +203,7 @@ describe("a reading in another unit than its marker's", () => {
       confidence: { analyte: 1, value: 1, unit: 1, range: 1 },
       biomarkerMatch: "existing" as const,
       markerUnit,
+      markerAnalyteKey: null,
       duplicateOf: null,
     });
     const [same, other, fresh] = seedReviewRows(
@@ -212,3 +216,85 @@ describe("a reading in another unit than its marker's", () => {
     expect(fresh.confirmed).toBe(true);
   });
 });
+
+describe("a reading in another unit that can be converted", () => {
+  // Glucose stated in mmol/L against a marker kept in mg/dL, and the analyte is
+  // known: Save converts it, so nothing blocks and the row starts selected.
+  const glucose = (overrides: Partial<OcrReviewRow> = {}) =>
+    row({
+      analyte: "Glucose",
+      value: 5.6,
+      unit: "mmol/L",
+      markerUnit: "mg/dL",
+      markerAnalyteKey: "fasting-glucose",
+      ...overrides,
+    });
+
+  it("previews what Save will store, beside what the report stated", () => {
+    const conversion = readingConversion(glucose());
+    expect(conversion).toMatchObject({
+      unit: "mg/dL",
+      statedValue: 5.6,
+      statedUnit: "mmol/L",
+    });
+    expect(conversion!.value).toBeCloseTo(5.6 * 18.0182, 9);
+  });
+
+  it("is not blocked, and not a validation error", () => {
+    expect(readingUnitDiffers(glucose())).toBe(true);
+    expect(readingUnitBlocked(glucose())).toBe(false);
+    expect(validateReviewRow(glucose())).toEqual({});
+  });
+
+  it("sends what the report printed, for the server to convert", () => {
+    const payload = toCommitRow(glucose());
+    expect(payload).toMatchObject({
+      analyte: "Glucose",
+      value: 5.6,
+      unit: "mmol/L",
+    });
+    expect(planSave([glucose()]).kind).toBe("ready");
+  });
+
+  it("starts selected on the review screen", () => {
+    const dto = {
+      analyte: "Glucose",
+      value: 5.6,
+      valueText: null,
+      unit: "mmol/L",
+      referenceLow: null,
+      referenceHigh: null,
+      referenceText: null,
+      takenAt: "2026-06-10",
+      confidence: { analyte: 1, value: 1, unit: 1, range: 1 },
+      biomarkerMatch: "existing" as const,
+      markerUnit: "mg/dL",
+      markerAnalyteKey: "fasting-glucose",
+      duplicateOf: null,
+    };
+    const [converts, blocked] = seedReviewRows(
+      [dto, { ...dto, markerAnalyteKey: null }],
+      null,
+    );
+    expect(converts.confirmed).toBe(true);
+    expect(blocked.confirmed).toBe(false);
+  });
+
+  it("stays blocked when the marker has no known analyte, or the pair is not in the registry", () => {
+    expect(readingUnitBlocked(glucose({ markerAnalyteKey: null }))).toBe(true);
+    expect(readingConversion(glucose({ markerAnalyteKey: null }))).toBeNull();
+    expect(validateReviewRow(glucose({ markerAnalyteKey: null }))).toEqual({
+      unitMismatch: true,
+    });
+    // The analyte is known but the unit is not one it reaches.
+    expect(readingUnitBlocked(glucose({ unit: "%" }))).toBe(true);
+  });
+
+  it("has nothing to preview when the units agree or the row is qualitative", () => {
+    expect(readingConversion(glucose({ unit: "mg/dL" }))).toBeNull();
+    expect(
+      readingConversion(glucose({ value: null, valueText: "negative" })),
+    ).toBeNull();
+    expect(readingConversion(glucose({ value: null }))).toBeNull();
+  });
+});

src/components/labs/__tests__/ocr-row-editor.test.tsx

@@ -19,6 +19,7 @@ const baseRow: OcrReviewRow = {
   confidence: { analyte: 1, value: 1, unit: 1, range: 1 },
   biomarkerMatch: "existing",
   markerUnit: "mmol/L",
+  markerAnalyteKey: null,
   duplicateOf: null,
   confirmed: true,
 };
@@ -155,3 +156,42 @@ describe("<OcrRowEditor> unit differs from the marker's", () => {
     expect(html).toContain("Geführt in mmol/L; dieser Befund nennt mg/dL");
   });
 });
+
+describe("<OcrRowEditor> unit differs but converts", () => {
+  const converts: OcrReviewRow = {
+    ...baseRow,
+    analyte: "Glucose",
+    value: 5.6,
+    takenAt: "2026-06-10",
+    unit: "mmol/L",
+    markerUnit: "mg/dL",
+    markerAnalyteKey: "fasting-glucose",
+  };
+
+  it("says what Save will store and what the report stated, not that it is blocked", () => {
+    const html = render(undefined, "en", converts);
+    expect(html).toContain('data-slot="ocr-row-converted-badge"');
+    expect(html).toContain("Saved as 100.9 mg/dL, converted from 5.6 mmol/L");
+    expect(html).not.toContain("Tracked in");
+    expect(html).not.toContain('aria-invalid="true"');
+  });
+
+  it("speaks German too", () => {
+    const html = render(undefined, "de", converts);
+    expect(html).toContain("umgerechnet aus 5,6 mmol/L");
+  });
+
+  it("shows nothing when the units agree", () => {
+    const html = render(undefined, "en", { ...converts, unit: "mg/dL" });
+    expect(html).not.toContain("ocr-row-converted-badge");
+  });
+
+  it("still says it is blocked when the analyte is not known", () => {
+    const html = render(undefined, "en", {
+      ...converts,
+      markerAnalyteKey: null,
+    });
+    expect(html).toContain("Tracked in mg/dL; this report says mmol/L");
+    expect(html).not.toContain("ocr-row-converted-badge");
+  });
+});

src/components/labs/lab-converted-note.tsx

@@ -0,0 +1,44 @@
+"use client";
+
+import { useTranslations } from "@/lib/i18n/context";
+import { formatLabValue } from "@/lib/labs/format-value";
+
+import { useLabNumber } from "./use-lab-format";
+
+/**
+ * A quiet "converted from 5.6 mmol/L" beside a reading whose stored number is a
+ * conversion of what the report printed, so a number nobody typed can always be
+ * traced back. Renders nothing for a reading stored as stated.
+ */
+export function LabConvertedNote({
+  reading,
+  className,
+}: {
+  reading: {
+    converted: boolean;
+    sourceValue: number | null;
+    sourceUnit: string | null;
+  };
+  className?: string;
+}) {
+  const { t } = useTranslations();
+  const labNumber = useLabNumber();
+  if (
+    !reading.converted ||
+    reading.sourceValue === null ||
+    reading.sourceUnit === null
+  ) {
+    return null;
+  }
+  return (
+    <span
+      data-slot="lab-converted-note"
+      className={className ?? "text-muted-foreground text-xs"}
+    >
+      {t("labs.convertedFrom", {
+        value: formatLabValue(reading.sourceValue, labNumber),
+        unit: reading.sourceUnit,
+      })}
+    </span>
+  );
+}

src/components/labs/lab-history-list.tsx

@@ -30,6 +30,7 @@ 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 { formatLabReading } from "@/lib/labs/format-value";
+import { LabConvertedNote } from "./lab-converted-note";
 import { resolveNoteForUpdate } from "@/lib/labs/note-update";
 import { useTranslations } from "@/lib/i18n/context";
 import { queryKeys } from "@/lib/query-keys";
@@ -381,6 +382,10 @@ export function LabHistoryList({ readings }: { readings: LabResultDto[] }) {
             <div className="min-w-0 flex-1 space-y-2">
               <div className="font-semibold tabular-nums">
                 {formatLabReading(r, labNumber)}
+                <LabConvertedNote
+                  reading={r}
+                  className="text-muted-foreground ml-2 text-xs font-normal"
+                />
               </div>
               <LabReferenceRangeBar
                 value={r.value}
@@ -453,6 +458,10 @@ export function LabHistoryList({ readings }: { readings: LabResultDto[] }) {
                 <TableCell className="font-semibold tabular-nums">
                   <div className="space-y-2">
                     <span>{formatLabReading(r, labNumber)}</span>
+                    <LabConvertedNote
+                      reading={r}
+                      className="text-muted-foreground block text-xs font-normal"
+                    />
                     <LabReferenceRangeBar
                       value={r.value}
                       referenceLow={r.referenceLow}

src/components/labs/lab-list.tsx

@@ -15,6 +15,7 @@ import { Skeleton } from "@/components/ui/skeleton";
 import { apiGet } from "@/lib/api/api-fetch";
 import { formatReferenceRange } from "@/lib/labs/reference-range";
 import { formatLabReading } from "@/lib/labs/format-value";
+import { LabConvertedNote } from "./lab-converted-note";
 import { useTranslations } from "@/lib/i18n/context";
 import { cn } from "@/lib/utils";
 import { queryKeys } from "@/lib/query-keys";
@@ -299,6 +300,7 @@ export function LabList({
                       {formatLabReading(group.latest, labNumber)}
                     </span>
                     <span>{labDate(group.latest.takenAt)}</span>
+                    <LabConvertedNote reading={group.latest} />
                   </div>
                 </div>
               );
@@ -429,6 +431,7 @@ export function LabList({
                     <span className="text-xs">
                       {labDate(group.latest.takenAt)}
                     </span>
+                    <LabConvertedNote reading={group.latest} />
                     {group.readings.length > 1 ? (
                       <span className="text-xs">
                         {t("labs.readingsCount", {

src/components/labs/ocr-review-types.ts

@@ -7,7 +7,7 @@
  */
 import type { OcrExtractedRowDto } from "@/lib/validations/labs-ocr";
 
-import { readingUnitDiffers } from "./ocr-review-validation";
+import { readingUnitBlocked } from "./ocr-review-validation";
 
 export interface OcrReviewRow {
   /** Stable client key for the list (the analyte+index at seed time). */
@@ -26,9 +26,12 @@ export interface OcrReviewRow {
   biomarkerMatch: "new" | "existing";
   /**
    * The unit the matched marker is tracked in; null for a marker that does not
-   * exist yet. A numeric row whose `unit` differs from it cannot be saved.
+   * exist yet. A numeric row whose `unit` differs from it is converted on
+   * Save when it can be (see `readingConversion`) and cannot be saved when not.
    */
   markerUnit: string | null;
+  /** Which analyte the matched marker is (conversion registry key), or null. */
+  markerAnalyteKey: string | null;
   /** Non-null when the server flagged a likely duplicate of a live reading. */
   duplicateOf: string | null;
   /** Whether the row is selected for saving. Defaults false for duplicates. */
@@ -53,17 +56,21 @@ export function seedReviewRows(
     confidence: row.confidence,
     biomarkerMatch: row.biomarkerMatch,
     markerUnit: row.markerUnit,
+    markerAnalyteKey: row.markerAnalyteKey,
     duplicateOf: row.duplicateOf,
     // A flagged duplicate starts unchecked, and so does a reading in another
-    // unit than its marker's (it carries a badge saying why, and ticking it
-    // marks the unit field until it is fixed); everything else starts
-    // confirmed.
+    // unit than its marker's that cannot be converted (it carries a badge
+    // saying why, and ticking it marks the unit field until it is fixed); a
+    // reading that converts starts confirmed, with a badge saying what Save
+    // will store; everything else starts confirmed.
     confirmed:
       row.duplicateOf === null &&
-      !readingUnitDiffers({
+      !readingUnitBlocked({
+        value: row.value,
         valueText: row.valueText,
         unit: row.unit,
         markerUnit: row.markerUnit,
+        markerAnalyteKey: row.markerAnalyteKey,
       }),
   }));
 }

src/components/labs/ocr-review-validation.ts

@@ -7,6 +7,7 @@
  * build the payload: it returns null exactly when `validateReviewRow` reports
  * at least one field.
  */
+import { convertLabValue } from "@/lib/labs/unit-conversion/convert";
 import { sameLabUnit } from "@/lib/labs/unit-normalise";
 
 import type { OcrReviewRow } from "./ocr-review-types";
@@ -46,6 +47,60 @@ export function readingUnitDiffers(row: {
   return !sameLabUnit(stated, row.markerUnit);
 }
 
+/**
+ * What Save will store for a numeric row whose unit differs from its marker's
+ * and can be converted: the value in the marker's unit, beside what the report
+ * stated. Null when the units agree, the row is qualitative, or the pair has no
+ * conversion. The commit does the same conversion on the server; this only lets
+ * the screen say so before Save.
+ */
+export function readingConversion(row: {
+  value: number | null | undefined;
+  valueText: string | null | undefined;
+  unit: string | null | undefined;
+  markerUnit: string | null | undefined;
+  markerAnalyteKey: string | null | undefined;
+}): {
+  value: number;
+  unit: string;
+  statedValue: number;
+  statedUnit: string;
+} | null {
+  if (!readingUnitDiffers(row)) return null;
+  if (row.value === null || row.value === undefined) return null;
+  if (!Number.isFinite(row.value)) return null;
+  const statedUnit = (row.unit ?? "").trim();
+  const converted = convertLabValue({
+    analyteKey: row.markerAnalyteKey,
+    value: row.value,
+    from: statedUnit,
+    to: row.markerUnit as string,
+  });
+  if (!converted.ok) return null;
+  return {
+    value: converted.value,
+    unit: row.markerUnit as string,
+    statedValue: row.value,
+    statedUnit,
+  };
+}
+
+/**
+ * A numeric reading in another unit than its marker's that cannot be
+ * converted: the one case that still cannot be saved. A row with no number yet
+ * has nothing to convert, so it is blocked here as well as on `value`.
+ */
+export function readingUnitBlocked(row: {
+  value: number | null | undefined;
+  valueText: string | null | undefined;
+  unit: string | null | undefined;
+  markerUnit: string | null | undefined;
+  markerAnalyteKey: string | null | undefined;
+}): boolean {
+  if (!readingUnitDiffers(row)) return false;
+  return readingConversion(row) === null;
+}
+
 export function validateReviewRow(row: OcrReviewRow): OcrRowErrors {
   const errors: OcrRowErrors = {};
   if (!row.analyte.trim()) errors.analyte = true;
@@ -56,7 +111,7 @@ export function validateReviewRow(row: OcrReviewRow): OcrRowErrors {
   } else {
     if (row.value === null || !Number.isFinite(row.value)) errors.value = true;
     if (!(row.unit ?? "").trim()) errors.unit = true;
-    if (readingUnitDiffers(row)) errors.unitMismatch = true;
+    if (readingUnitBlocked(row)) errors.unitMismatch = true;
   }
   return errors;
 }
@@ -80,7 +135,7 @@ export function toCommitRow(row: OcrReviewRow): OcrCommitRowInput | null {
   if (row.value === null || !Number.isFinite(row.value)) return null;
   const unit = (row.unit ?? "").trim();
   if (!unit) return null;
-  if (readingUnitDiffers(row)) return null;
+  if (readingUnitBlocked(row)) return null;
   return {
     analyte,
     value: row.value,

src/components/labs/ocr-row-editor.tsx

@@ -32,7 +32,12 @@ import { Label } from "@/components/ui/label";
 import { useTranslations } from "@/lib/i18n/context";
 
 import type { OcrReviewRow } from "./ocr-review-types";
-import { readingUnitDiffers, type OcrRowErrors } from "./ocr-review-validation";
+import {
+  readingConversion,
+  readingUnitBlocked,
+  type OcrRowErrors,
+} from "./ocr-review-validation";
+import { useLabNumber } from "./use-lab-format";
 
 /** Below this per-field confidence the field is flagged for a second look. */
 const CONFIDENCE_THRESHOLD = 0.6;
@@ -76,10 +81,13 @@ export function OcrRowEditor({
         message={t(messageKey, params)}
       />
     ) : null;
-  // Stated before Save, not only after a failed attempt: a reading in another
-  // unit than its marker's cannot be written, and the person should see why
-  // the row is unticked (or will not save) while they are still reading it.
-  const unitDiffers = readingUnitDiffers(row);
+  // Stated before Save, not only after a failed attempt. A reading in another
+  // unit than its marker's is either converted (the badge says what Save will
+  // store) or cannot be written (the person should see why the row is unticked,
+  // or will not save, while they are still reading it).
+  const unitBlocked = readingUnitBlocked(row);
+  const conversion = readingConversion(row);
+  const labNumber = useLabNumber();
 
   const isQualitative = row.valueText !== null && row.valueText !== undefined;
   const lowValueConfidence =
@@ -169,7 +177,7 @@ export function OcrRowEditor({
                   {t("labs.ocr.duplicateWarning")}
                 </Badge>
               ) : null}
-              {unitDiffers ? (
+              {unitBlocked ? (
                 <Badge variant="secondary" className="max-w-full">
                   <Ruler aria-hidden />
                   <span className="truncate">
@@ -180,6 +188,23 @@ export function OcrRowEditor({
                   </span>
                 </Badge>
               ) : null}
+              {conversion ? (
+                <Badge
+                  variant="outline"
+                  className="max-w-full"
+                  data-slot="ocr-row-converted-badge"
+                >
+                  <Ruler aria-hidden />
+                  <span className="truncate">
+                    {t("labs.ocr.unitConvertedBadge", {
+                      value: labNumber(conversion.value),
+                      markerUnit: conversion.unit,
+                      statedValue: labNumber(conversion.statedValue),
+                      unit: conversion.statedUnit,
+                    })}
+                  </span>
+                </Badge>
+              ) : null}
               {lowRowConfidence ? (
                 <Badge variant="secondary" className="text-muted-foreground">
                   <AlertCircle aria-hidden />

src/lib/labs/ocr-extract.ts

@@ -28,6 +28,8 @@ import {
   isUnreadableRange,
   parseReferenceRange,
 } from "@/lib/labs/parse-reference-range";
+import { matchAnalyteKey } from "@/lib/labs/analyte-match";
+import { sameLabUnit } from "@/lib/labs/unit-normalise";
 import { annotate } from "@/lib/logging/context";
 import {
   extractedLabsSchema,
@@ -144,8 +146,17 @@ export async function annotateRow(
   // Biomarker match — case-insensitive on the catalog identity, presence-only.
   const existingBiomarker = await prisma.biomarker.findFirst({
     where: { userId, name: { equals: analyte, mode: "insensitive" } },
-    select: { id: true, unit: true },
+    select: { id: true, name: true, unit: true, analyteKey: true },
   });
+  // The analyte the marker is, so the review can say whether a row in another
+  // unit converts. Read only: the key is filled when a reading is written.
+  const markerAnalyteKey = existingBiomarker
+    ? (existingBiomarker.analyteKey ??
+      matchAnalyteKey({
+        name: existingBiomarker.name,
+        unit: existingBiomarker.unit,
+      }))
+    : null;
 
   // Duplicate check: a live lab_results row with the same analyte (fuzzy,
   // case-insensitive), the same calendar day, and the same value/valueText is
@@ -161,7 +172,14 @@ export async function annotateRow(
         analyte: { equals: analyte, mode: "insensitive" },
         takenAt: labReadingDaySearchRange(takenAt),
       },
-      select: { id: true, value: true, valueText: true, takenAt: true },
+      select: {
+        id: true,
+        value: true,
+        valueText: true,
+        sourceValue: true,
+        sourceUnit: true,
+        takenAt: true,
+      },
       take: 100,
     });
     const candidates = rows.filter(
@@ -172,6 +190,20 @@ export async function annotateRow(
         duplicateOf = c.id;
         break;
       }
+      // A reading stored converted holds the number in its marker's unit; what
+      // the report printed is beside it. The same number in the same unit is
+      // the same reading (the commit applies the same rule).
+      if (
+        row.value !== null &&
+        row.unit !== null &&
+        c.sourceValue !== null &&
+        c.sourceValue === row.value &&
+        c.sourceUnit !== null &&
+        sameLabUnit(c.sourceUnit, row.unit)
+      ) {
+        duplicateOf = c.id;
+        break;
+      }
       if (
         row.valueText !== null &&
         c.valueText !== null &&
@@ -199,6 +231,7 @@ export async function annotateRow(
     confidence: row.confidence,
     biomarkerMatch: existingBiomarker ? "existing" : "new",
     markerUnit: existingBiomarker?.unit ?? null,
+    markerAnalyteKey,
     duplicateOf,
   };
 }

src/lib/openapi/routes/ocr.ts

@@ -75,7 +75,11 @@ const extractedRow = z
     biomarkerMatch: z.enum(["new", "existing"]),
     markerUnit: z.string().nullable().meta({
       description:
-        "The unit the matched marker is tracked in, or null when the marker does not exist yet (it will adopt this row's unit). A row whose `unit` differs from it cannot be committed: the commit skips it with `reason: unit_mismatch`, and the review screen marks it before Save.",
+        "The unit the matched marker is tracked in, or null when the marker does not exist yet (it will adopt this row's unit). A row whose `unit` differs from it is converted on commit when the marker's analyte is known and the pair is in the unit-conversion registry; otherwise the commit skips it with `reason: unit_mismatch`, and the review screen marks it before Save.",
+    }),
+    markerAnalyteKey: z.string().nullable().meta({
+      description:
+        "The analyte the matched marker is (the unit-conversion registry's key, e.g. `fasting-glucose`), or null when the marker does not exist yet or its name matches none. With `markerUnit` it tells a client whether a row in another unit can be converted on commit.",
     }),
     duplicateOf: z.string().nullable(),
   })

src/lib/validations/labs-ocr.ts

@@ -131,6 +131,12 @@ export interface OcrExtractedRowDto {
    * so before Save when the scanned unit differs.
    */
   markerUnit: string | null;
+  /**
+   * Which analyte the matched marker is (unit-conversion registry key), or null
+   * when the marker is new or none is known. With `markerUnit` it tells the
+   * review screen whether a row in another unit can be converted on Save.
+   */
+  markerAnalyteKey: string | null;
   duplicateOf: string | null;
 }
 

tests/integration/labs-unit-conversion.test.ts

@@ -250,6 +250,48 @@ describe("the OCR commit", () => {
     expect(json.data!.skipped.map((s) => s.reason)).toEqual(["duplicate"]);
   });
 
+  it("tells the scan review which analyte the marker is, and flags a re-scan as a duplicate", async () => {
+    const { annotateRow } = await import("@/lib/labs/ocr-extract");
+    const scanned = {
+      analyte: "Glucose",
+      value: 5.0,
+      valueText: null,
+      unit: "mmol/L",
+      referenceLow: null,
+      referenceHigh: null,
+      referenceText: null,
+      takenAt: "2026-06-01",
+      confidence: { analyte: 1, value: 1, unit: 1, range: 1 },
+    };
+    const annotated = await annotateRow(USER, scanned, "2026-06-01", "UTC");
+    expect(annotated).toMatchObject({
+      biomarkerMatch: "existing",
+      markerUnit: "mg/dL",
+      markerAnalyteKey: "fasting-glucose",
+    });
+    // The converted reading from the commit above holds 90.09 mg/dL; the scan
+    // says 5.0 mmol/L, which is what the report printed for it.
+    expect(annotated.duplicateOf).not.toBeNull();
+
+    // A different value is not a duplicate.
+    const other = await annotateRow(
+      USER,
+      { ...scanned, value: 6.5 },
+      "2026-06-01",
+      "UTC",
+    );
+    expect(other.duplicateOf).toBeNull();
+
+    // A marker the registry knows nothing about reports no analyte.
+    const free = await annotateRow(
+      USER,
+      { ...scanned, analyte: "My own marker", unit: "mg/dL" },
+      "2026-06-01",
+      "UTC",
+    );
+    expect(free.markerAnalyteKey).toBeNull();
+  });
+
   it("skips a row whose unit cannot be converted, as before", async () => {
     const { json } = await call<{
       inserted: unknown[];