HbA1c (Glycated Haemoglobin)
What Is This Test?
The HbA1c (Glycated Hemoglobin) test is a blood test that measures the average blood sugar (glucose) level over the past 2 to 3 months. It works by measuring the percentage of hemoglobin (the oxygen-carrying protein in red blood cells) that has glucose attached to it.
Unlike a fasting blood sugar test, the HbA1c test reflects long-term glucose control and is widely used to diagnose prediabetes, diabetes mellitus, and monitor the effectiveness of diabetes treatment.
Since red blood cells live for approximately 120 days, the HbA1c level provides an estimate of your average blood glucose over this period.
Why this test is performed?
Doctors may recommend the HbA1c test to:
- Diagnose prediabetes
- Diagnose Type 1 and Type 2 diabetes
- Monitor long-term blood sugar control
- Assess the effectiveness of diabetes treatment
- Evaluate the risk of diabetes complications
- Screen people at high risk of diabetes
- Monitor gestational diabetes after pregnancy (when appropriate)
- Support routine diabetes management
Test Preparation
- No fasting is required.
- You may eat and drink normally before the test.
- Continue taking your medications unless your healthcare provider advises otherwise.
- Inform your doctor if you have:
- Anemia
- Recent blood transfusion
- Chronic kidney disease
- Hemoglobin disorders (e.g., sickle cell disease or thalassemia)
- Pregnancy
These conditions may affect the accuracy of HbA1c results.
Medical disclaimer
This article is for general information and education only. It is not medical advice, does not create a doctor–patient relationship, and is not a substitute for consultation with a qualified doctor who has assessed your individual situation. Never delay seeking medical advice because of something you have read here.
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