Which A1C value defines diabetes?

• A. <5.7%
• B. >6.5%
• C. 5.7-6.4%
• D. 6.0-6.9%

Answer: (B)

An A1C value is used to diagnose diabetes because it reflects average blood glucose over roughly the past two to three months, giving a longer-term picture than a single fingerstick result. Diabetes is diagnosed when the A1C crosses the threshold of 6.5% or higher, which places it in the diabetic range rather than normal or prediabetic ranges. Values below 5.7% are considered normal, 5.7% to 6.4% indicates prediabetes, and 6.0% to 6.9% spans both prediabetic and diabetic ranges, making it less precise as a diagnostic cutoff. Therefore, a value greater than 6.5% is the appropriate threshold used to define diabetes.