HbA1c explained: your 3-month blood sugar number

Published 26 October 2026 · Matt O'Brien

Three different men chatting over mugs of tea at a wooden table in a cosy cafe: a tall slim young Black man with short twists in a navy gilet over a white t-shirt, a stocky older white man with a bald head, white beard and glasses in a burgundy jumper, and a heavier-set East Asian man in his forties with short black hair in a green checked shirt

Short answer: an HbA1c test shows your average blood sugar over roughly the last 2 or 3 months, which is why it is used to spot prediabetes and diagnose type 2 diabetes. This applies to men of any age.

What does an HbA1c test show?

The NHS page on high blood sugar describes an HbA1c test as one done by a health professional to check your blood sugar level over the last 2 or 3 months.

That longer view gives you and your GP a steadier picture than a single reading taken on one day.

HbA1c normal range: what the numbers mean

In the UK, results are usually given in mmol/mol. You may also see a percentage. These are the levels NICE guidance on preventing type 2 diabetes uses:

HbA1c result	What NICE says it indicates
Below 42 mmol/mol (below 6.0%)	Below the high risk range
42 to 47 mmol/mol (6.0 to 6.4%)	High risk of type 2 diabetes, often called prediabetes
48 mmol/mol (6.5%) or above	Possible type 2 diabetes

NICE says that if a result is 48 or above and you have no symptoms, a second blood test should be done before type 2 diabetes is confirmed. The NHS notes these levels are a guide and can differ depending on your age and the type of diabetes you have, so check your own result with your doctor or care team.

What is prediabetes?

The NHS diabetes page explains that pre-diabetes, also called non-diabetic hyperglycaemia, means blood sugar above the normal range but not high enough to be diabetes. It raises your risk of type 2 diabetes, and that risk can be reduced through lifestyle changes. Some people may be eligible for the NHS Diabetes Prevention Programme.

NICE recommends a blood test at least once a year for people in the high risk range. Our guide to prediabetes covers what to do next.

Who should get an HbA1c test?

Not everyone with type 2 diabetes has symptoms. The NHS page on type 2 diabetes symptoms and diagnosis says you may be more at risk if:

you're white and over 40, or over 25 and from a South Asian, Chinese, Black African or Black Caribbean background
a parent, brother or sister has type 2 diabetes
you're overweight and not very physically active
you have a condition such as high blood pressure

If you're 40 to 74 and don't have an existing condition, you should be invited to a free NHS Health Check every 5 years, which includes a diabetes risk assessment. Younger than 40 or not invited? You don't have to wait: the NHS says to see a GP if you think you may have type 2 diabetes or have a higher risk.

If you already have type 2 diabetes, the NHS treatment page says your HbA1c is usually checked every 3 to 6 months.

Can a home test tell me if I have diabetes?

No. A home kit can be a starting point, but it cannot diagnose you. If a home result is raised, take it to your GP surgery, who can arrange a proper test. See our guides to reading results and weight-loss blood tests.

When to get help

Routine: speak to your GP surgery if you have symptoms of high blood sugar, such as feeling very thirsty, peeing a lot or feeling tired, and haven't been diagnosed with diabetes.
Not sure: call NHS 111 or use 111 online.
Emergency: call 999 or go to A&E if you think you have high blood sugar and you're being sick or have stomach pain, are breathing faster than usual, feel drowsy, or your breath smells fruity. Do not drive yourself to A&E.

From Matt

"If you have been putting off a conversation with your GP, book it. You do not need a polished speech. You could say: 'I want to talk about my weight and general health. My energy has changed, and I would like to understand my options.'"

An HbA1c result is a good reason to have that conversation.

Your next step

See what's in a baseline blood test on our blood tests page. I'm not a clinician, so talk to your GP about your own results.

FAQ

What does an HbA1c test show? Your average blood sugar over roughly the last 2 or 3 months.

What HbA1c level is prediabetes? NICE uses 42 to 47 mmol/mol (6.0 to 6.4%) as the high risk range.

What HbA1c level means diabetes? 48 mmol/mol (6.5%) or above, confirmed by a second test if you have no symptoms.

Sources

Last updated 26 October 2026.