Abstract
Optimal glycaemic control is crucial in patients with diabetes mellitus (DM) to avoid episodes of hypoglycaemia and both micro- and macrovascular complications. Diabetic control relies mainly on the evaluation of haemoglobin A1c (HbA1c), which is unfortunately unreliable in patients with haemoglobinopathies. This case report describes a patient with type 2 DM and haemoglobin J (HbJ) trait, which resulted in erratic HbA1c values throughout her follow-up. Other approaches, such as self-blood glucose monitoring, are needed to evaluate glycaemic control instead of relying on HbA1c alone to guide the management DM in these patients.