Effect of frozen whole blood store conditions on ion-exchange high performance liquid chromatography for hemoglobin A1c detection

Objective To explore the effects of different store temperatures and periods of time on the test results of hemoglobin A1c（HbA1c）. Methods Whole blood HbA1c was detected by ion-exchange high performance liquid chromatography（HPLC）.Sixty fresh blood samples were collected.Each sample was divided into 15 groups.Group 1 was tested immediately as a control,groups 2-6 were stored at 4℃ and tested after 3 days,1,2,3,and 4 weeks,respectively.Groups 7-9,groups 10-12 and groups 13-15 were stored at-20℃,at-40℃,and at-80℃,and tested after 1,3,and 6 months,respectively.Average values of HbA1c at different store conditions were compared. Results The HbA1c in samples stored at 4℃ for 2 weeks was 2.5%,which was higher than that in control group,began to gradually decrease from 3 weeks and was lower than 7.2% from 4 weeks.The HbA1c in samples stored at-20℃ and-40℃ for 1,3,and 6 months was lower in groups 2-15 than in control group,and decreased gradually with the prolongation of time.The HbA1c was statistically different in all other groups except for group 13 compared with control group（P＜0.05）.The HbA1c in samples stored at-80℃ for 1,3,and 6 months was higher than that after stored for 1 day and had a less deviation than that stored at-20℃ and-40℃. Conclusion The shorter the store time is,the closer the HbA1c value is to the control at the same store temperature.The lower the temperature is,the closer the HbA1c value is to the control at the same store time.The store temperature has a greater effect on HbA1c value than store time.The best store condition of blood samples for HbA1c is at-80℃ for 1 month.