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What Is Hemoglobin A1c (HbA1c)?
Hemoglobin is the oxygen-carrying pigment that gives blood its red color and 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 referred to as glycosylated or glucosylated hemoglobin.
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