Understanding HbA1c: Your 3-Month Diabetes Report Card

Many patients check fasting sugar regularly yet have never heard of HbA1c — or do the test without understanding it. HbA1c is the single most important number in long-term diabetes care.

What exactly is HbA1c?

Glucose in your blood slowly attaches to haemoglobin inside red blood cells. Since red cells live about 120 days, the percentage of "sugar-coated" haemoglobin reflects your average blood sugar over the past three months. A single fasting reading can be manipulated by one careful day; HbA1c cannot.

What do the numbers mean?

• Below 5.7% — normal
• 5.7% – 6.4% — prediabetes; the ideal window to act and often reverse the trend
• 6.5% and above — diabetes

For most people with diabetes, the treatment target is below 7%. Your doctor may set a slightly higher or lower target depending on your age, other illnesses, and risk of hypoglycaemia — targets are individual.

Why it matters so much

Every 1% reduction in HbA1c meaningfully lowers the risk of diabetic complications — kidney damage, eye damage, nerve damage, and heart disease. Two patients with the same fasting sugar can have very different HbA1c values, and it is the HbA1c that better predicts complications.

How often should you test?

Every 3 months if treatment is being adjusted or targets are not met; every 6 months once you are stable at target. It requires no fasting and can be done at any time of day.

Common misunderstandings

"My fasting sugar is fine, so I'm fine." Post-meal spikes can keep HbA1c high even with normal fasting values.

"I only need medicines when sugar is high." Diabetes medication works by keeping the average down every single day — stopping and restarting defeats the purpose and shows up in your HbA1c.

The bottom line: know your HbA1c, know your target, and review it with your doctor every visit. It is the report card that matters.