HbA1c (Glycated Haemoglobin)
HbA1c — also called glycated haemoglobin or A1C — measures the percentage of haemoglobin in your blood that has glucose attached to it. Because red blood cells live for roughly 2–3 months, HbA1c gives a reliable window into your average blood-sugar control over that period, unlike a fasting glucose test which only captures a single moment.
Normal Range
Below 5.7% (non-diabetic); 5.7–6.4% pre-diabetes; 6.5%+ diabetes
Reference ranges may vary slightly between laboratories. Always interpret your result in context with your doctor.
Why is HbA1c measured?
Doctors use HbA1c to diagnose pre-diabetes and type 2 diabetes, to monitor how well blood sugar is controlled in people already diagnosed, and to assess cardiovascular and kidney risk, since prolonged high glucose damages blood vessels and nerves.
High HbA1c means…
An HbA1c above 5.7% indicates your average blood glucose has been elevated. A result of 5.7–6.4% is classified as pre-diabetes; 6.5% or higher on two separate tests confirms type 2 diabetes. Values above 8% suggest poor glycaemic control and increased risk of diabetes complications.
Low HbA1c means…
HbA1c below 4% is rare and may indicate hypoglycaemia, haemolytic anaemia, or certain blood disorders. People taking insulin or diabetes medications sometimes see very low values, which can signal a risk of dangerously low blood sugar episodes.
Symptoms associated with abnormal HbA1c
When HbA1c is high:
- Increased thirst and frequent urination
- Unexplained fatigue and blurred vision
- Slow-healing cuts or wounds
- Tingling or numbness in hands and feet
- Recurrent infections
When HbA1c is low:
- Shakiness, sweating, and rapid heartbeat
- Confusion or difficulty concentrating
- Pale skin and hunger
How to improve your HbA1c
- Eat fewer refined carbohydrates and sugary drinks — swap white rice and bread for whole grains.
- Even a 30-minute walk after meals significantly reduces post-meal glucose spikes.
- Losing 5–7% of body weight if overweight can lower HbA1c by 0.5–1%.
- Retest every 3 months if managing diabetes; annually if pre-diabetic.
- Sleep quality matters — poor sleep raises cortisol and blood sugar; aim for 7–9 hours.
Frequently asked questions about HbA1c
What is a normal HbA1c level?
For adults without diabetes, a normal HbA1c is below 5.7%. Values between 5.7% and 6.4% indicate pre-diabetes, and 6.5% or above on two tests confirms type 2 diabetes. For people already managing diabetes, most guidelines recommend a target below 7%.
How often should I test my HbA1c?
If you have diabetes, testing every 3 months is standard. For pre-diabetes, every 6–12 months. For healthy adults over 35 with no risk factors, a test every 3 years is typically recommended by the US Preventive Services Task Force.
Can I lower my HbA1c without medication?
Yes, lifestyle changes can significantly lower HbA1c. Studies show that a combination of dietary changes (reducing simple carbohydrates), regular aerobic exercise, and weight loss can reduce HbA1c by 1–2% — comparable to some oral diabetes medications.
Does HbA1c testing require fasting?
No. HbA1c measures a 2–3 month average and is not affected by what you ate recently. You do not need to fast before an HbA1c blood test, making it more convenient than fasting glucose tests.
What conditions make HbA1c inaccurate?
Conditions that affect red blood cell lifespan — such as haemolytic anaemia, sickle cell disease, iron deficiency anaemia, and recent blood transfusions — can make HbA1c falsely high or low. Your doctor may order alternative tests like fructosamine in these cases.
Medical Sources
- ↗ American Diabetes Association — HbA1c Standards
- ↗ WHO Diabetes Diagnosis Criteria
- ↗ NIH MedlinePlus — A1C Test
This page is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider about your individual results.