Hemoglobin A1c Test

About Hemoglobin A1c Test

To assist with control of blood glucose levels, the American Diabetes Association (ADA) has recommended glycated hemoglobin testing (HbA1c) twice a year for patients with stable glycemia, and quarterly for patients with poor glucose control. Interpretative ranges are based on ADA guidelines.

How it works? 

The Hemoglobin A1C test (also called the glycated hemoglobin test) measures the average blood sugar level over the past two to three months. It does this by analyzing how much glucose has attached itself to hemoglobin—a protein found in red blood cells that carries oxygen and gives blood its red color. When glucose is present in the bloodstream, it naturally binds to hemoglobin. This process forms what's called glycated hemoglobin, with the A1C subtype being the most common form measured in this test. Once glucose attaches to a hemoglobin molecule, it stays there for the life of the red blood cell;typically about 120 days.

The more glucose in the blood, the higher the amount of glycated hemoglobin. Since red blood cells are constantly dying and being replaced, the A1C level reflects a moving average of blood sugar over the previous few months. By measuring the percentage of hemoglobin that is glycated, the A1C test provides a reliable picture of long-term glucose control.