BiomarkersHbA1c

Blood sugar

HbA1c

Your average blood sugar over about 3 months

On your report it may say: A1c, Glycated haemoglobin

HbA1c shows how much sugar has stuck to your red blood cells over their lifetime, giving a 2–3 month average. It doesn't need fasting and is a key test for diagnosing and tracking diabetes.

Updated 2026-10-26

Typical ranges · %

In range below 5.7
Prediabetes 5.7–6.5
Diabetes range 6.5+

mmol/mol = (% − 2.15) × 10.929

Anaemia, thalassaemia trait and some hemoglobin variants can make HbA1c misleading.

Ranges vary by lab, age and sex. The range printed on your report applies.

If it's low

A low HbA1c is usually fine, but can be falsely low with blood loss or some anaemias.

Common causes

  • Healthy blood sugar
  • Recent blood loss or transfusion

What you might notice

  • None

If it's high

Your average blood sugar has been high over recent months.

Common causes

  • Insulin resistance
  • Excess weight
  • Low activity
  • Family history
  • Iron deficiency can falsely raise it

What you might notice

  • Often none
  • Thirst
  • Tiredness

Testing

Who should test
All adults over 30, and anyone with risk factors or abnormal fasting glucose.
How to prepare
No fasting needed.
When to retest
Every 3 months while making changes; yearly if normal.

What can help

SYNC doesn't change your plan from this result alone. Use these only alongside your doctor's advice.

Food sources

Fibre-rich grains and pulsesVegetables at every mealProtein with carbsFewer sweets and sugary drinks

See a doctor if HbA1c is 5.7% or above.

Common questions

Why doesn't it need fasting?

It reflects months, not today's meals.

Can low iron change HbA1c?

Yes, iron deficiency can push it up falsely.

Explore further

Sources

  1. MedlinePlus (US National Library of Medicine): Hemoglobin A1C (HbA1c) test

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For general education only, not medical advice. Ranges shown are typical for adults; the range printed on your lab report applies. Talk to a qualified doctor about your results.