diff --git a/IRaCIS.Core.Application/Service/ReadingCalculate/OCTCalculateService.cs b/IRaCIS.Core.Application/Service/ReadingCalculate/OCTCalculateService.cs
index 9e6c67a0e..f84acadca 100644
--- a/IRaCIS.Core.Application/Service/ReadingCalculate/OCTCalculateService.cs
+++ b/IRaCIS.Core.Application/Service/ReadingCalculate/OCTCalculateService.cs
@@ -1301,7 +1301,7 @@ namespace IRaCIS.Core.Application.Service.ReadingCalculate
         public async Task<decimal?> GetAvgLipidAngle(ReadingCalculateDto inDto)
         {
             return inDto.QuestionInfo.Where(x => x.LesionType == LesionType.ROI).SelectMany(x => x.TableRowInfoList).SelectMany(x => x.TableQuestionList)
-             .Where(x => x.QuestionMark == QuestionMark.LipidAngle).Select(x => x.Answer.IsNullOrEmptyReturn0()).DefaultIfEmpty(0).Average();
+             .Where(x => x.QuestionMark == QuestionMark.LipidAngle&&x.Answer.IsNotNullOrEmpty()).Select(x => x.Answer.IsNullOrEmptyReturn0()).DefaultIfEmpty(0).Average();
         }