Glucose-6-phosphate dehydrogenase deficiency diagnosed in an adolescent with type 1 diabetes mellitus and hemoglobin A1c discordant with blood glucose measurements.

Disorders of hemolysis reduce the exposure time of hemoglobin to glucose, resulting in a falsely low hemoglobin A1c level. This case report describes the unexpected diagnosis of glucose-6-phosphate dehydrogenase deficiency made during evaluation of discordant HbA1c and blood glucose measurements.