Hemoglobin A1C

A1c stands for glycated hemoglobin. The A1c percentage measures how much sugar is attached to the blood's hemoglobin protein. The A1c test result gives a measure of how well your body has controlled the amount of sugar in the blood over the past two to three months.

The ADA says that an A1c level at or above 6.5% means you have diabetes. Selvin's team showed that the risk of diabetes, heart disease, and death rises with A1c.

Compared to people with a normal A1c level of 5.0% to 5.5%, they found that:

  • An A1c level of less than 5.0% means a 48% lower risk of diabetes and about the same risk of heart disease.
  • An A1c level of 5.5% to 6.0% means an 86% higher risk of diabetes and a 23% higher risk of heart disease.
  • An A1c level of 6.0% to 6.5% means a 4.5-fold higher risk of diabetes and a 78% higher risk of heart disease.
  • An A1c level of 6.5% or more means a 16.5-fold higher risk of diabetes and a twofold higher risk of heart disease.

For this reason, the A1c test is not as prone as the fasting glucose test to individual fluctuations due to stress or illness.