As of 2015, the normal range for blood sugar with the hemoglobin A1c test is anything below 5.7 percent, says the National Institute of Diabetes and Digestive and Kidney Diseases. The HbA1c test is a blood test that measures the average level of glucose over the past three months.
The HbA1c test is reported as a percentage, and the higher the percentage, the higher the level of blood glucose. The test is also used to diagnose Type 2 diabetes and prediabetes, states the NIDDK. Health care providers use the test after the diagnosis of diabetes has been made to determine if patients are meeting their treatment goals.