HEMOGLOBIN WAYNE VARIANT INTERFERING WITH HEMOGLOBIN A1C MEASUREMENT.

Objective: To describe the effect of hemoglobin Wayne variant on hemoglobin A1c (A1c) accuracy and to stress the importance of patient-physician communication and trust.

Methods: We present the clinical history and laboratory findings of 2 patients, with a review of related literature.

Results: Two older patients were diagnosed with diabetes mellitus (DM) and suffered from frequent hypoglycemia resulting from titrating their diabetes medications based on an extremely elevated A1c (>11% [97 mmol/mol]) obtained through high-performance liquid chromatography. Discrepancies were noticed between their blood glucose logs and their A1c results. Ultimately, both were found to have heterogenous hemoglobin Wayne variant by hemoglobin electrophoresis. Repeat immunoassay found the A1c to be very low, in the 5 to 6.2% (31 to 44 mmol/mol) range. One of the patients did not even meet diagnostic criteria for DM.

Conclusion: A1c testing is susceptible to misinterpretation due to multiple interfering factors. Hemoglobin variants should be considered as a differential when there are discrepancies between A1c and blood glucose levels. Trust between the patient and the physician is essential in raising clinical suspicion and avoiding potentially lethal outcomes.