An HbA1c of 25%-Is It Real?

A 63-year-old healthy woman presented for routine diabetes screening as part of an annual wellness exam. She has no personal or family history of diabetes or anemia. Her hemoglobin (Hb)2 concentration was 13.4 g/dL. Her hemoglobin A1c (HbA1c) was strikingly high, at 25.4% (reportable range, 3.5%–19%), measured by the cation-exchange high-performance liquid chromatography (HPLC) method (Variant II Turbo, Bio-Rad). The WHO recommendations for use of HbA1c to diagnose diabetes mellitus use a cutoff of 15% is flagged for review. Of note, the patient had a normal fasting glucose and HbA1c in the past 2 years. This year, our laboratory switched HbA1c measurement from an immunoturbidimetric method (Tina-quant, Roche) to an HPLC method. The HPLC chromatogram of her HbA1c result showed a decreased fraction of nonglycohemoglobin A (HbA), and no variant peak was identified (Fig. 1). HbA1c is calculated as a percentage of the area of the “A1c” peaks in relation to the total area of hemoglobin peaks on the chromatogram. Fig. 1. HbA1c result of 25.4% measured by the HPLC method. Despite the …