Prediabetes: what an HbA1c of 42 to 47 means and what to do next
Short answer: an HbA1c of 42 to 47 mmol/mol means your blood sugar is higher than normal but not in the diabetes range. It is often called prediabetes, and it raises your risk of type 2 diabetes and heart disease. The good news is that changes to weight, diet and activity can bring it down, and many people return to the normal range.
What the numbers mean
Below 42 mmol/mol: normal.
42 to 47 mmol/mol: higher risk, often called prediabetes.
48 mmol/mol or above: in the diabetes range, usually confirmed with a repeat test.
See the HbA1c test and the diabetes status profile.
What to do next
Tell your GP. In England, people with an HbA1c of 42 to 47 can be referred to the free NHS Diabetes Prevention Programme.
Lose some weight if you need to. Even a modest loss lowers risk.
Move more: aim for at least 150 minutes of moderate activity a week.
Change what you eat: cut sugary drinks and refined carbohydrates, and eat more fibre, vegetables and pulses.
Check the rest: blood pressure, cholesterol and kidney function, because heart risk is raised too.
When to retest
Because HbA1c reflects the past two to three months, wait about three months after making changes to see their effect. UK guidance advises a check at least once a year.
Could the result be wrong?
HbA1c can be unreliable with anaemia, some inherited blood conditions, recent blood loss and pregnancy. A clinician may use a glucose test instead.
When not to wait
If you have excessive thirst, passing urine very often, unexplained weight loss or blurred vision, see your GP promptly.
Frequently asked questions
Is prediabetes reversible?
For many people, yes. Lifestyle changes can bring HbA1c back below 42.
Should I also test insulin?
An insulin resistance test can add detail, but it is not used to diagnose diabetes in the UK.
Do I need to fast for HbA1c?
No.
Sources
NICE public health guideline PH38: type 2 diabetes, prevention in people at high risk
NHS England: NHS Diabetes Prevention Programme
Diabetes UK: prediabetes
Related reading
Clinically reviewed by Zak Toon, ACP, on 15 October 2026.
This article is general information based on UK guidance. It is not personal medical advice. If you are worried about your health or have symptoms, speak to your GP or call 111.
