diff --git a/app/services/qualys_service.py b/app/services/qualys_service.py
index e094ca4..a0ece44 100644
--- a/app/services/qualys_service.py
+++ b/app/services/qualys_service.py
@@ -627,9 +627,9 @@ def _refresh_all_agents_impl(db, mode="diff"):
         criteria = [{"field": "tagName", "operator": "CONTAINS", "value": tag_filter}]
         if last_id:
             criteria.append({"field": "id", "operator": "GREATER", "value": str(last_id)})
-        # Mode diff : ajoute filtre lastCheckedIn > timestamp dernier diff sync
+        # Mode diff : filtre 'updated' > dernier sync (champ searchable Qualys QPS)
         if mode == "diff" and last_diff_iso:
-            criteria.append({"field": "lastCheckedIn", "operator": "GREATER", "value": last_diff_iso})
+            criteria.append({"field": "updated", "operator": "GREATER", "value": last_diff_iso})
         payload = {"ServiceRequest": {
             "preferences": {"limitResults": 100},
             "filters": {"Criteria": criteria}