Diabetes Test — HbA1c (3-Month Sugar Average)

What this test checks

HbA1c measures the percentage of your red blood cells that are coated with sugar. Because red blood cells live around 3 months, this gives a stable average of your blood sugar over that time — a much fuller picture than a single fasting reading.

Why do people get this test?

It is the standard test to diagnose diabetes and to track how well diabetes is being controlled. One reading tells you and your doctor whether your sugar levels have been healthy across many weeks, not just on the day of the test.

When you should consider this test

• You have been told you are at risk of diabetes
• Family history of diabetes or thyroid issues
• Frequent urination, increased thirst, or unexplained tiredness
• Already living with diabetes — retest every 3 to 6 months
• Overweight, low physical activity, or over 40 years old

How to prepare

No fasting required. You can eat and drink normally before the test.