Hemoglobin A1C (HbA1c) Test Test
The hemoglobin A1C test shows your average blood sugar level over the past two to three months. It helps diagnose or monitor diabetes and prediabetes.
What this test measures
A hemoglobin A1C (HbA1C) test is a blood test that shows your average level of blood glucose, also called blood sugar, over the past two to three months. It measures the percentage of your red blood cells that have glucose-coated hemoglobin.
What your results mean
Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.
Higher-than-normal results
High A1C levels are a sign of high blood glucose from diabetes. Diabetes can cause serious health problems, including heart disease, kidney disease, and nerve damage.
Frequently asked questions
What does the A1C test measure?
It measures the percentage of your red blood cells that have glucose-coated hemoglobin, giving an average blood sugar level over the past two to three months.
How is the A1C test used?
It is used to screen for or diagnose type 2 diabetes and prediabetes, and to monitor blood glucose control in people with diabetes.
What do the A1C numbers mean for diagnosis?
According to MedlinePlus, normal is below 5.7%, prediabetes is 5.7% to 6.4%, and diabetes is 6.5% or higher.
Can the A1C test diagnose type 1 diabetes?
No, the A1C test is not used to diagnose type 1 diabetes, but it may be used for monitoring blood glucose levels.
What should I do if my A1C result is high?
If your result was higher than normal, your provider may repeat the test or use another diabetes test. Talk with your provider about what your results mean.
Related lab tests
Sources
- MedlinePlus: Hemoglobin A1C (HbA1c) Test — NIH MedlinePlus
Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.