Plasma glucose and HbA1c discrepancy may indicate hemoglobinopathy: a case series

Diabetes Mellitus is a chronic disease characterised by elevated plasma glucose (PG) levels. HbA1c has been widely utilized for diabetes diagnosis. However, certain conditions restrict its use. In such cases, plasma glucose (PG) measurements and self-monitoring blood glucose (SMBG) are recommended. This case series highlights the importance of considering both HbA1c and PG or SMBG in the evaluation of patients with diabetes. This case series presents three cases of patients with diabetes who exhibited a discrepancy between PG and HbA1c levels. Only one patient demonstrated isolated microcytosis, while the remaining two had completely normal hematologic profiles. Due to this discrepancy, hemoglobin electrophoresis was conducted, revealing various hemoglobinopathies in all cases. For patients with discrepancies between PG levels and HbA1c, we suggest a thorough evaluation that includes consideration of potential hemoglobinopathies. These hemoglobin variants can present with isolated microcytosis or entirely normal hematologic parameters and may lead to falsely low HbA1c values. In cases of discordance between PG and HbA1c, hemoglobin electrophoresis can serve as a valuable diagnostic tool. Identifying hemoglobinopathies before determining treatment regimens can help mitigate the risk of complications from inadequate treatment, and awareness of HbA1c limitations allows clinicians to use both HbA1c and PG/SMBG to optimize diabetes management and minimize the risk of diabetic complications.