Delay in diagnosis of diabetes mellitus due to inaccurate use of hemoglobin A1C levels.

Testing of hemoglobin A(1C) (HbA(1C)) levels has become widespread in the management of patients with diabetes mellitus. Since the 1980s, it has proven to be an invaluable tool correlating with a patient's average blood glucose levels as well as with their disease morbidity. Clinicians often base treatment decisions and make adjustments depending on a patient's HbA(1C) level.