To diagnose diabetes, HbA1c must be at least what value on two occasions?

• A. 6.5% or higher
• B. 7.0% or higher
• C. 6.0% or higher
• D. 7.5% or higher

Answer: (A)

HbA1c reflects average blood glucose over about 2–3 months by measuring the proportion of glycated hemoglobin. For diagnosing diabetes, the threshold is 6.5% or higher, and it must be confirmed on two separate occasions to ensure the result isn’t due to lab error or a temporary fluctuation. This level corresponds to roughly an average glucose of about 140 mg/dL, so two measurements at or above 6.5% confirm persistent hyperglycemia rather than a one-time spike. Values below that, like 6.0%, fall into the prediabetes range, while higher values such as 7.0% or 7.5% are not by themselves the diagnostic criterion unless confirmed on two tests.