diff --git a/src/api/v1/endpoints/anomaly.py b/src/api/v1/endpoints/anomaly.py
index ed16927..a3e3fe8 100644
--- a/src/api/v1/endpoints/anomaly.py
+++ b/src/api/v1/endpoints/anomaly.py
@@ -30,7 +30,14 @@ async def detect_anomalies(
 
     service = get_anomaly_service()
 
-    values = [float(r.get(request.value_field, 0)) for r in request.data]
+    values = []
+    for r in request.data:
+        val = r.get(request.value_field)
+        if val is not None:
+            try:
+                values.append(float(val))
+            except (TypeError, ValueError):
+                pass
 
     if not values:
         return {