Unexpected Detection of Abnormal Hemoglobin Variants During Routine HbA۱c Analysis by HPLC Technique: Challenges and Opportunities in HbA۱c Testing

Background: Glycated Hemoglobin A۱c (HbA۱c) assay is most widely used in diabetic patients for assessing long-term control of glycemia. The presence of hemoglobin variants may be an incidental finding and can interfere with HbA۱c measurements. The aim of the present study is to investigate the prevalence and impact of interference of different abnormal hemoglobin variants on HbA۱c measurements during routine HbA۱c testing. Methods: A total of ۱۲,۰۹۲ HbA۱c samples were collected from January to August ۲۰۱۸. HbA۱c quantification was carried out on a Variant II Bio-Rad’s HPLC analyzer. Abnormal chromatograms were further analyzed using the extended-run high-pressure liquid chromatography (HPLC) analysis in the A۲/F mode. Results: The samples were examined for presence of abnormal variants. Samples producing abnormal chromatograms were further analyzed in A۲/F mode to characterize hemoglobin variants. Abnormal variants were identified in ۱۲۶ (۱%) samples, and ۷۴ (۰.۵۹%) sickle cell traits (SCT) were the most common variant in our findings. Moreover, ۳۰ (۰.۲۴%) cases were eluted in the variant window in A۱c mode, which on further analysis were found to be Hb E & Hb D traits. Furthermore, ۳ (۰.۰۲%) cases were eluted at a RT <۱ min as (unknown) and identified as Hb H. Also,۱۹ (۰.۱۵%) samples were eluted in the P۳ window at different retention times. Conclusion: Observing each chromatograph after the analysis can help us in identifying silent hemoglobin variants in routine HbA۱c testing. Knowledge and awareness of common hemoglobin variants affecting measurement of HbA۱c is imperative to avoid reporting of falsely low HbA۱c values in diabetic population.

کلیدواژه ها:

Diabetes mellitus ، HbA۱c ، Hemoglobin variant ، HPLC