diff --git a/IRaCIS.Core.API/HostService/DicomSCPService.cs b/IRaCIS.Core.API/HostService/DicomSCPService.cs
index 1774dac80..85fbaeb89 100644
--- a/IRaCIS.Core.API/HostService/DicomSCPService.cs
+++ b/IRaCIS.Core.API/HostService/DicomSCPService.cs
@@ -170,7 +170,7 @@ namespace IRaCIS.Core.API.HostService
             string accessionNumber = request.Dataset.GetSingleValueOrDefault(DicomTag.AccessionNumber, string.Empty);
 
 
-            if (patientID.IsNullOrEmpty() && patientName.IsNullOrEmpty() && studyInstanceUID.IsNullOrEmpty() && studyDate.IsNullOrEmpty() && accessionNumber.IsNotNullOrEmpty())
+            if (patientID.IsNullOrEmpty() && patientName.IsNullOrEmpty() && studyInstanceUID.IsNullOrEmpty() && studyDate.IsNullOrEmpty() && accessionNumber.IsNullOrEmpty())
             {
                 yield return new DicomCFindResponse(request, DicomStatus.MissingAttribute);
                 yield break;