What does a low HbA1c result mean?

A low HbA1c result (below the reference range, e.g., <4% or <20 mmol/mol) indicates that your average blood glucose over the past 2–3 months has been unusually low. This can point to recurrent hypoglycemia, often due to overtreatment of diabetes (excess insulin or sulfonylureas), or rare conditions like insulinoma. It can also be artificially lowered by blood loss, hemolytic anemias, or hemoglobin variants (e.g., sickle cell disease). In non-diabetic individuals, a low HbA1c is usually benign but warrants medical evaluation to rule out underlying pathology. Importantly, HbA1c is not a diagnostic test for hypoglycemia—repeated fasting or continuous glucose monitoring is needed. Evidence is strong (clinical guidelines, large cohorts). Caveat: single measurements can be misleading due to blood disorders or pregnancy. Always consult a doctor for interpretation.