A1C of 6.5%: The Diabetes Diagnosis Threshold

What 6.5% means

The American Diabetes Association (ADA) lists an A1C of 6.5% or higher as one of the ways diabetes is diagnosed, alongside a fasting plasma glucose of 126 mg/dL (7.0 mmol/L) or higher, a 2-hour glucose of 200 mg/dL (11.1 mmol/L) or higher during a glucose tolerance test, or a random glucose of 200 mg/dL or higher in someone with classic symptoms. An A1C of 6.5% matches an estimated average glucose of about 140 mg/dL (7.8 mmol/L). Check yours in the A1C calculator.

Why a second result is needed

Without unmistakable symptoms of high blood sugar, the ADA says diagnosis requires two abnormal results from different tests, which can be taken at the same time. If the results disagree, the one above the cut point is repeated. This guards against labeling someone on the strength of a single reading that could be off for reasons such as anemia, a hemoglobin variant, or lab variation.

When A1C may not be the right test

The ADA notes that A1C can be misleading in some situations, including some hemoglobin variants, pregnancy, anemia, treatment with erythropoietin, and hemodialysis. In those cases clinicians rely on glucose tests instead. NIDDK also says the A1C test needs no fasting.

Questions to bring to your appointment

• Do I need another test to confirm, and which one?
• Is there anything about my health that could affect my A1C result?
• If it is confirmed, what is the plan, who is on my care team, and what support is available to learn about diabetes?
• What A1C goal should I aim for? (See an A1C of 7.)

Being told you are in the diabetes range is a lot to take in. It is common, it is manageable, and you do not have to work it out alone. Our blog directory lists people who write honestly about life with diabetes.

Information only, not medical advice. Your care team may set different targets for you, and only a lab test ordered by a clinician can diagnose diabetes or prediabetes. See our medical disclaimer.