HbA1c value of 6.5% or higher is diagnostic for diabetes mellitus.

• A. True
• B. False
• C. Only if fasting plasma glucose is elevated
• D. Only if random glucose is elevated

Answer: (A)

HbA1c reflects average blood glucose over roughly the past 2–3 months. An HbA1c of 6.5% or higher is one of the established diagnostic thresholds for diabetes, meaning that sustained hyperglycemia meets the criteria regardless of fasting status. This makes the test convenient and reliable because it doesn’t require a patient to fast and it captures longer-term glucose exposure. In practice, a diagnosis can be made if this level is confirmed on a subsequent test, or if there are unmistakable hyperglycemic symptoms with a high random glucose, but the essential point is that 6.5% or above by HbA1c is diagnostic. The other statements implying that fasting or random glucose must be elevated are not necessary when the HbA1c criterion is met.