What is HbA1c?
A glycosylated Hemoglobin (HbA1c) is a lab test to measure how much sugar has been in your blood over the past 2-3 months. It is used to detect prediabetes, diagnose diabetes as a part of health checkups, and monitor treatment efficacy. HbA1c values are considered normal if <5.7%, while values ≥ 6.5% are indicative of diabetes.
The higher the HbA1c, the greater the risk of complications. People having diabetes should take this test regularly to monitor their glucose levels and regulate the treatment decision. A proper schedule of exercise, healthy eating, and medication can assist in bringing down the level.
Why is HbA1c done?
The Glycosylated Hemoglobin test is performed to:
Monitor Diabetes treatment efficacy by measuring glycosylated hemoglobin regularly
Screen for Diabetes as part of regular health checkup, as well as in patients with high risk of developing diabetes
Diagnose and confirm diabetes with a combination of other tests if blood sugar levels have been high over a long period of time
What does HbA1c Measure?
Glycosylated Hemoglobin Test measures the percentage of glycosylated hemoglobin in blood which reflects the average blood glucose over a period of past two to three months (8 - 12 weeks).
Hemoglobin is the protein found in Red Blood Cells and is responsible for transporting oxygen. Of the different types of hemoglobin, Hemoglobin A is predominant. With the elevation of blood sugar levels, some glucose binds spontaneously to Hemoglobin A (this binding is called Glycosylation or Glycation) and remains bound for the complete lifetime of the RBC, which is 120 days normally. Higher the level of glucose in the blood, greater is the amount of it binding to Hemoglobin A. Hemoglobin A1c is the dominant form of Glycated Hemoglobin. As RBCs die and are replaced, Hemoglobin A1c is cleared and slowly replaced with non-glycosylated hemoglobin. Measurement of HbA1c level over a period of time gives an indication of the level of glucose in the blood over the specified period of time. This helps in the diagnosis of Diabetes and is useful for monitoring the effectiveness of measures taken to reduce blood sugar levels.
Interpreting HbA1c results
Normal: Below 5.7% (39 mmol/mol approx.)
Prediabetic: 5.7% - 6.4% (39 to 46 mmol/mol approx.)
Diabetic: Above 6.5% (above 48 mmol/mol approx.)
Less than 5.7% Glycated Hemoglobin indicates normal levels of blood sugar. Increased risk of developing Diabetes is found in Prediabetic patients with blood sugar level between 5.7% and 6.4%. Patients with a HbA1c level greater than 6.5% are usually diagnosed with Diabetes.