Hemoglobin A1c (HbA1c) is a form of haemoglobin with attached glucose (glycated haemoglobin). The test evaluates measures the average amount of glucose in the blood over a period of 8 - 12 weeks.
Hemoglobin is a protein found in inside red blood cells that is responsible for carrying oxygen. The predominant type is called haemoglobin A and available glucose that circulates in the blood binds to this type of haemoglobin forming glycated haemoglobin. The more glucose circulating in the blood the more glycated haemoglobin is formed. The glucose remains binded for the lifespan of the red blood cells (120days).
HbA1c may be used to screen for and diagnose diabetes or monitoring those on treatment. It is important to evaluate glucose control over time and an HbA1c < 7% indicates good glucose control and is also associated with a lower risk of complications.
HbA1c may be ordered during general health screens or when diagnosis of diabetes is suspected including:
Signs or symptoms of hyperglycemia (high blood glucose levels)
General risk factors for developing diabetes
-Annually as part of general health screening or individuals at risk
-On demand testing when signs or symptoms are present
-Twice per year for patients on treatment to monitor glucose control