The glycosylated hemoglobin test (A1c, also called hemoglobin A1c or the glycosylated hemoglobin test) is an important blood test to diagnose diabetes or determine control of your diabetes. It provides an average blood glucose measurement over the past 3 months and is used in conjunction with home glucose monitoring to make treatment adjustments.

The normal range for the A1c test is less than 5.7% for people without diabetes, 5.7%-6.4% for those with pre-diabetes. For people with diabetes, it is 6.5% or higher. For diagnostic purposes, two separate A1c tests at 6.5% are positive for diabetes.

People with diabetes who are treated with insulin should have this test 4 times a year (every 3 months). The test may be needed more frequently when your diabetes is not well-controlled. However, the test should be performed no more often than every 6 weeks. Those who are not treated with insulin should have this test every 4 to 6 months.

  • If your A1c is 12.0%: Your average mean daily plasma blood sugar is around this (mg/dl): 298.
  • If your A1c is 11.0%: Your average mean daily plasma blood sugar is around this (mg/dl): 269.
  • If your A1c is 10.0%: Your average mean daily plasma blood sugar is around this (mg/dl): 240.
  • If your A1c is 9.0%: Your average mean daily plasma blood sugar is around this (mg/dl): 212.
  • If your A1c is 8.0%: Your average mean daily plasma blood sugar is around this (mg/dl): 183.
  • If your A1c is 7.0%: Your average mean daily plasma blood sugar is around this (mg/dl): 154.
  • If your A1c is 6.0%: Your average mean daily plasma blood sugar is around this (mg/dl): 126.
  • If your A1c is 5.0%: Your average mean daily plasma blood sugar is around this (mg/dl): 97.