diff --git a/IRaCIS.Core.Application/Service/Allocation/TaskConsistentRuleService.cs b/IRaCIS.Core.Application/Service/Allocation/TaskConsistentRuleService.cs
index 82a04ee8a..7bcd4ccea 100644
--- a/IRaCIS.Core.Application/Service/Allocation/TaskConsistentRuleService.cs
+++ b/IRaCIS.Core.Application/Service/Allocation/TaskConsistentRuleService.cs
@@ -156,7 +156,7 @@ namespace IRaCIS.Core.Application.Service
                     {
                         var maxCodeStr = _visitTaskRepository.Where(t => t.TrialId == subject.TrialId && t.TrialReadingCriterionId == trialReadingCriterionId).OrderByDescending(t => t.BlindSubjectCode).Select(t => t.BlindSubjectCode).FirstOrDefault();
 
-                        if (maxCodeStr != String.Empty)
+                        if ( !string.IsNullOrEmpty(maxCodeStr))
                         {
                             int.TryParse(maxCodeStr.Substring(maxCodeStr.Length - filterObj.BlindSubjectNumberOfPlaces), out maxCodeInt);