diff --git a/src/frontend/flask_app/static/js/vision_overlay.js b/src/frontend/flask_app/static/js/vision_overlay.js
index 6b2b648..fbbd873 100644
--- a/src/frontend/flask_app/static/js/vision_overlay.js
+++ b/src/frontend/flask_app/static/js/vision_overlay.js
@@ -249,15 +249,15 @@ var VisionOverlay = (function () {
       var pt = null;
       for (var i = 0; i < order.length && !pt; i++) pt = anchor(order[i]);
       if (!pt) return;
-      // #118: valore null/undefined/vuoto = quota non misurata (Number(null) e' 0): nessuna etichetta
-      if (r.value === null || r.value === undefined || r.value === '' || typeof r.value === 'boolean') return;
-      var v = Number(r.value);
-      if (!isFinite(v)) return;
+      // #118: valore null/undefined/vuoto/non finito = quota non misurata (Number(null) e' 0): etichetta NaN, status della riga (fail)
+      var v = (r.value === null || r.value === undefined || r.value === '' || typeof r.value === 'boolean')
+        ? NaN : Number(r.value);
+      var txt = isFinite(v) ? v.toFixed(3) : 'NaN';
       out.push({
         key: r.key,
         x: pt.x,
         y: pt.y,
-        text: r.name + ' ' + v.toFixed(3) + ' ' + (r.unit || ''),
+        text: r.name + ' ' + txt + ' ' + (r.unit || ''),
         status: r.status,
       });
     });
diff --git a/src/frontend/flask_app/tests/js/test_vision_overlay.js b/src/frontend/flask_app/tests/js/test_vision_overlay.js
index 63f7f54..ccb944e 100644
--- a/src/frontend/flask_app/tests/js/test_vision_overlay.js
+++ b/src/frontend/flask_app/tests/js/test_vision_overlay.js
@@ -224,17 +224,18 @@ const rows = fixture.measurements.map((m) => {
   check('labels: testo name + valore a 3 decimali + unit', f[0].text === 'T 1.500 mm', f[0].text);
 }
 
-// --- #118: labels, valore null/undefined/non finito -> nessuna etichetta ---
+// --- #118: labels, valore null/undefined/non finito -> etichetta NaN con status della riga ---
 {
   const ov = [{ type: 'segment', role: 'found', tool_id: 't', row1: 10, col1: 10, row2: 10, col2: 20 }];
   const mk = (value) => ({ key: 1, name: 'T', value, unit: 'mm', status: 'fail', vision_output: 't.value' });
-  check('labels: value null -> nessuna etichetta (Number(null) e\' 0)', VisionOverlay.labels([mk(null)], ov).length === 0);
-  check('labels: value undefined -> nessuna', VisionOverlay.labels([mk(undefined)], ov).length === 0);
-  check('labels: value NaN/Infinity -> nessuna',
-    VisionOverlay.labels([mk(NaN), mk(Infinity), mk(-Infinity)], ov).length === 0);
-  check('labels: value 0 resta un valore valido', VisionOverlay.labels([mk(0)], ov).length === 1);
+  const nan = (v) => { const l = VisionOverlay.labels([mk(v)], ov); return l.length === 1 && l[0].text === 'T NaN mm' && l[0].status === 'fail'; };
+  check('labels: value null -> etichetta NaN, status fail (Number(null) e 0)', nan(null));
+  check('labels: value undefined / stringa vuota -> etichetta NaN', nan(undefined) && nan(''));
+  check('labels: value NaN/Infinity -> etichetta NaN', nan(NaN) && nan(Infinity) && nan(-Infinity));
+  check('labels: value 0 resta un valore valido', VisionOverlay.labels([mk(0)], ov)[0].text === 'T 0.000 mm');
   const misto = VisionOverlay.labels([{ ...mk(null), key: 1 }, { ...mk(2.5), key: 2 }], ov);
-  check('labels: null saltata, le altre righe restano', misto.length === 1 && misto[0].key === 2);
+  check('labels: null e valida entrambe presenti', misto.length === 2 && misto[0].text === 'T NaN mm' && misto[1].key === 2);
+  check('labels: riga NaN senza ancoraggio -> nessuna etichetta', VisionOverlay.labels([mk(null)], []).length === 0);
 }
 
 // --- #121: svg(overlay, opts) ---