The A1C test reflects the average of a person's blood glucose levels over the past three months and is reported as a percentage, according to the National Diabetes Information Clearinghouse. A normal A1C level is less than 5.7 percent.
An A1C level of 5.7 to 6.4 percent indicates prediabetes. People with an A1C level greater than 6 percent are considered at very high risk for type 2 diabetes. A level of 6.5 percent or higher means a person has diabetes, the National Diabetes Information Clearinghouse states.
The test does not show daily fluctuations in blood sugar levels and does not require fasting. It is used to detect prediabetes and type 2 diabetes, but is not recommended for the diagnosis of type 1 diabetes or gestational (pregnancy-associated) diabetes.