i18n(labs): say why a biomarker's unit cannot change once it has readings

messages/de.json

@@ -135,6 +135,11 @@
         "required": "Bestätige dein aktuelles Passwort, um das zu ändern.",
         "failed": "Die Bestätigung ist fehlgeschlagen. Es wurde nichts geändert."
       }
+    },
+    "biomarkers": {
+      "unit": {
+        "locked": "Dieser Marker hat schon Werte, deshalb kannst du seine Einheit nicht ändern. Die gespeicherten Werte würden sonst in der neuen Einheit angezeigt, ohne umgerechnet zu werden."
+      }
     }
   },
   "doctorReport": {
@@ -8917,6 +8922,7 @@
         "namePlaceholder": "z. B. LDL-Cholesterin",
         "unit": "Einheit",
         "unitPlaceholder": "z. B. mg/dl",
+        "unitLockedHint": "Sobald dieser Marker Werte hat, bleibt seine Einheit, wie sie ist. Sonst würden die gespeicherten Werte in einer neuen Einheit angezeigt, ohne umgerechnet zu werden.",
         "panel": "Panel",
         "panelPlaceholder": "z. B. Lipide",
         "lowerBound": "Referenz unten",

messages/en.json

@@ -135,6 +135,11 @@
         "required": "Confirm your current password to change this.",
         "failed": "That did not verify. Nothing was changed."
       }
+    },
+    "biomarkers": {
+      "unit": {
+        "locked": "This marker already has readings, so its unit can't be changed. The stored values would be shown in the new unit without being converted."
+      }
     }
   },
   "doctorReport": {
@@ -8917,6 +8922,7 @@
         "namePlaceholder": "e.g. LDL cholesterol",
         "unit": "Unit",
         "unitPlaceholder": "e.g. mg/dL",
+        "unitLockedHint": "Once this marker has readings, its unit stays as it is. The stored values would otherwise be shown in a new unit without being converted.",
         "panel": "Panel",
         "panelPlaceholder": "e.g. Lipids",
         "lowerBound": "Reference low",

messages/es.json

@@ -135,6 +135,11 @@
         "required": "Confirma tu contraseña actual para cambiar esto.",
         "failed": "La verificación ha fallado. No se ha cambiado nada."
       }
+    },
+    "biomarkers": {
+      "unit": {
+        "locked": "Este marcador ya tiene valores, así que no puedes cambiar su unidad. Los valores guardados se mostrarían en la nueva unidad sin convertirse."
+      }
     }
   },
   "doctorReport": {
@@ -8917,6 +8922,7 @@
         "namePlaceholder": "p. ej. Colesterol LDL",
         "unit": "Unidad",
         "unitPlaceholder": "p. ej. mg/dL",
+        "unitLockedHint": "Cuando este marcador ya tiene valores, su unidad no cambia. De lo contrario, los valores guardados se mostrarían en una unidad nueva sin convertirse.",
         "panel": "Panel",
         "panelPlaceholder": "p. ej. Lípidos",
         "lowerBound": "Referencia mínima",

messages/fr.json

@@ -135,6 +135,11 @@
         "required": "Confirmez votre mot de passe actuel pour modifier ceci.",
         "failed": "La vérification a échoué. Rien n'a été modifié."
       }
+    },
+    "biomarkers": {
+      "unit": {
+        "locked": "Ce marqueur a déjà des valeurs, son unité ne peut donc pas être modifiée. Les valeurs enregistrées s'afficheraient dans la nouvelle unité sans être converties."
+      }
     }
   },
   "doctorReport": {
@@ -8917,6 +8922,7 @@
         "namePlaceholder": "ex. Cholestérol LDL",
         "unit": "Unité",
         "unitPlaceholder": "ex. mg/dL",
+        "unitLockedHint": "Dès que ce marqueur a des valeurs, son unité reste la même. Sinon, les valeurs enregistrées s'afficheraient dans une nouvelle unité sans être converties.",
         "panel": "Panel",
         "panelPlaceholder": "ex. Lipides",
         "lowerBound": "Référence basse",

messages/it.json

@@ -135,6 +135,11 @@
         "required": "Conferma la password attuale per modificarlo.",
         "failed": "La verifica non è riuscita. Non è stato modificato nulla."
       }
+    },
+    "biomarkers": {
+      "unit": {
+        "locked": "Questo marcatore ha già dei valori, quindi non puoi cambiarne l'unità. I valori salvati verrebbero mostrati nella nuova unità senza essere convertiti."
+      }
     }
   },
   "doctorReport": {
@@ -8917,6 +8922,7 @@
         "namePlaceholder": "es. Colesterolo LDL",
         "unit": "Unità",
         "unitPlaceholder": "es. mg/dL",
+        "unitLockedHint": "Quando questo marcatore ha già dei valori, la sua unità resta invariata. Altrimenti i valori salvati verrebbero mostrati in una nuova unità senza essere convertiti.",
         "panel": "Panel",
         "panelPlaceholder": "es. Lipidi",
         "lowerBound": "Riferimento minimo",

messages/ko.json

@@ -135,6 +135,11 @@
         "required": "변경하려면 현재 비밀번호를 확인하세요.",
         "failed": "확인에 실패했습니다. 아무것도 변경되지 않았습니다."
       }
+    },
+    "biomarkers": {
+      "unit": {
+        "locked": "이 마커에는 이미 기록된 값이 있어서 단위를 바꿀 수 없어요. 저장된 값이 변환되지 않은 채 새 단위로 표시되기 때문이에요."
+      }
     }
   },
   "doctorReport": {
@@ -8917,6 +8922,7 @@
         "namePlaceholder": "예: LDL 콜레스테롤",
         "unit": "단위",
         "unitPlaceholder": "예: mg/dL",
+        "unitLockedHint": "이 마커에 기록된 값이 있으면 단위는 그대로 유지돼요. 그렇지 않으면 저장된 값이 변환되지 않은 채 새 단위로 표시돼요.",
         "panel": "패널",
         "panelPlaceholder": "예: 지질",
         "lowerBound": "참고 하한",

messages/pl.json

@@ -135,6 +135,11 @@
         "required": "Potwierdź obecne hasło, aby to zmienić.",
         "failed": "Weryfikacja nie powiodła się. Nic nie zostało zmienione."
       }
+    },
+    "biomarkers": {
+      "unit": {
+        "locked": "Ten marker ma już wyniki, więc nie możesz zmienić jego jednostki. Zapisane wartości byłyby pokazywane w nowej jednostce bez przeliczenia."
+      }
     }
   },
   "doctorReport": {
@@ -8917,6 +8922,7 @@
         "namePlaceholder": "np. Cholesterol LDL",
         "unit": "Jednostka",
         "unitPlaceholder": "np. mg/dl",
+        "unitLockedHint": "Gdy ten marker ma już wyniki, jego jednostka pozostaje bez zmian. W przeciwnym razie zapisane wartości byłyby pokazywane w nowej jednostce bez przeliczenia.",
         "panel": "Panel",
         "panelPlaceholder": "np. Lipidy",
         "lowerBound": "Dolna granica",

src/components/labs/__tests__/biomarker-form.test.tsx

@@ -0,0 +1,80 @@
+import { describe, it, expect, vi } from "vitest";
+import { renderToStaticMarkup } from "react-dom/server";
+
+import { I18nProvider } from "@/lib/i18n/context";
+import { ApiError } from "@/lib/api/api-fetch";
+import { localizedApiError } from "@/lib/api/localized-error";
+import en from "../../../../messages/en.json";
+
+/**
+ * The marker editor says, before a save, that a marker's unit stays as it is
+ * once readings exist, and the refusal the server sends for such a change
+ * reads as that sentence rather than the generic save error.
+ */
+
+vi.mock("@/lib/api/api-fetch", async (importOriginal) => ({
+  ...(await importOriginal<typeof import("@/lib/api/api-fetch")>()),
+  apiPost: vi.fn(),
+  apiPut: vi.fn(),
+}));
+
+import { BiomarkerForm } from "../biomarker-form";
+import type { BiomarkerDto } from "../types";
+
+const MARKER: BiomarkerDto = {
+  id: "bm-1",
+  name: "Glucose",
+  unit: "mg/dL",
+  lowerBound: 70,
+  upperBound: 99,
+  panel: null,
+  hasContext: false,
+  context: null,
+  hidden: false,
+  createdAt: "2026-01-01T00:00:00.000Z",
+  updatedAt: "2026-01-01T00:00:00.000Z",
+};
+
+function render(node: React.ReactNode) {
+  return renderToStaticMarkup(
+    <I18nProvider initialLocale="en">{node}</I18nProvider>,
+  );
+}
+
+describe("<BiomarkerForm> unit lock", () => {
+  const hint = en.labs.biomarker.form.unitLockedHint;
+
+  it("tells the editor of an existing marker that the unit is locked by readings", () => {
+    const html = render(<BiomarkerForm existing={MARKER} />);
+    expect(hint.length).toBeGreaterThan(0);
+    expect(html).toContain(hint.replace(/'/g, "&#x27;"));
+    expect(html).toMatch(/aria-describedby="[^"]*-unit-hint"/);
+  });
+
+  it("says nothing of a lock while a new marker is defined", () => {
+    const html = render(<BiomarkerForm />);
+    expect(html).not.toContain(hint.replace(/'/g, "&#x27;"));
+  });
+
+  it("reads the server's refusal as its own sentence, not the save error", () => {
+    const err = new ApiError("locked", 422, {
+      errorCode: "biomarkers.unit.locked",
+      readingCount: 2,
+    });
+    const t = (key: string) => {
+      const value = key
+        .split(".")
+        .reduce<unknown>(
+          (node, part) =>
+            node && typeof node === "object"
+              ? (node as Record<string, unknown>)[part]
+              : undefined,
+          en,
+        );
+      return typeof value === "string" ? value : key;
+    };
+    expect(localizedApiError(err, t, "labs.biomarker.form.saveError")).toBe(
+      en.apiErrors.biomarkers.unit.locked,
+    );
+  });
+});