Comparison of HbA1c Levels During Off-site Health Checkups Measured by Different Methods

Abstract

Objective: We reported that HbA1c levels measured by enzymatic assay (EA) (EA-HbA1c) during off-site health checkups are lower than those measured by on-site high-performance liquid chromatography (HPLC) assay. The HbA1c measurement method of the laboratory facility at our related institution (Hakuhokai Central Hospital) was changed from HPLC assay to EA in February 2017.

Methods: In the present study, we compared the HbA1c levels before and after the change in the measurement method for those who underwent off-site health checkups at our hospital from February 2015 to January 2019. Subjects with fasting plasma glucose ≥126 mg/dL and those under treatment for diabetes mellitus were excluded. We divided the measurement period by HPLC assay (February 2015 to January 2017) and the measurement period by EA (February 2017 to January 2019), and further divided them into four periods for comparison. We also compared HPLC-HbA1c and EA-HbA1c for each adjacent period.

Results: As a result, EA-HbA1c levels were significantly lower than HPLC-HbA1c levels (p<0.001). Moreover, HbA1c levels were significantly lower during the period when HPLC assay was changed to EA in the comparison for each adjacent period (p<0.001).

Conclusion: The low levels of HbA1c were observed as the HbA1c measurement was changed from the HPLC assay to the enzymatic assay. Based on our previous reports, the cause of the low EA-HbA1c level was considered to be hemolysis associated with the transportation of the sample to the laboratory.