Hemoglobin A1c Test (HbA1c)
Facts and Definition of Hemoglobin A1c (HbA1c)
- Hemoglobin A1c, often abbreviated HbA1c, is a form of hemoglobin (a blood pigment that carries oxygen) that is bound to glucose.
- The blood test for HbA1c level is routinely performed in people with type 1 and type 2 diabetes mellitus.
- Blood HbA1c levels are reflective of how well diabetes is controlled.
- The normal range for level for hemoglobin A1c is less than 6%.
- HbA1c also is known as glycosylated, or glycated hemoglobin.
- HbA1c levels are reflective of blood glucose levels over the past six to eight weeks and do not reflect daily ups and downs of blood glucose.
- High HbA1c levels indicate poorer control of diabetes than levels in the normal range.
- HbA1c is typically measured to determine how well a type 1 or type 2 diabetes treatment plan (including medications, exercise, or dietary changes) is working.
What Is Hemoglobin A1c?
Hemoglobin is the oxygen-carrying pigment that gives blood its red color and is also the predominant protein in red blood cells. About 90% of hemoglobin is hemoglobin A (the "A" stands for adult type). Although one chemical component accounts for 92% of hemoglobin A, approximately 8% of hemoglobin A is made up of minor components that are chemically slightly different. These minor components include hemoglobin A1c, A1b, A1a1, and A1a2. Hemoglobin A1c (HbA1c) is a minor component of hemoglobin to which glucose is bound. HbA1c also is sometimes referred to as glycated, glycosylated hemoglobin, or glycohemoglobin.
Medically Reviewed by a Doctor on 9/19/2017
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