Your result explained — what 48 means, whether it's diabetes, and what to do next
Written by Trevor Sebuliba, Advanced Nurse Practitioner, BSc, MSc, NMP · Reviewed 2026
If you have just received a blood test result showing an HbA1c of 48 mmol/mol, you are likely feeling worried or confused. This article explains exactly what that number means, why it matters, and what you can expect to happen next — in plain English.
HbA1c (haemoglobin A1c, also called glycated haemoglobin) is a blood marker that reflects your average blood sugar level over the past 2 to 3 months. Unlike a fasting glucose test — which gives a single snapshot — HbA1c tells your doctor how well your body has been managing blood sugar over time.
Red blood cells live for about 90 days. During this time, glucose gradually sticks to haemoglobin (the protein in red blood cells). The higher your blood sugar, the more glucose attaches. The HbA1c test measures this and reports it as a percentage or, more commonly in the UK, in mmol/mol units.
| HbA1c (mmol/mol) | HbA1c (%) | What It Means |
|---|---|---|
| Below 42 | Below 6.0% | Normal — no diabetes |
| 42 – 47 | 6.0% – 6.4% | Pre-diabetes (high risk) |
| 48 or above | 6.5% or above | Diabetes (if confirmed) |
An HbA1c of 48 mmol/mol sits exactly at the diabetes diagnostic threshold. The NHS uses this cut-off because research consistently shows that blood sugar at this level and above begins to cause the long-term complications associated with diabetes — particularly damage to the eyes, kidneys, nerves, and blood vessels.
A single HbA1c of 48 mmol/mol in a person without symptoms is usually repeated before a formal diabetes diagnosis is made. NICE guidelines recommend a confirmatory second test if the person has no classic symptoms (such as excessive thirst, frequent urination, blurred vision, or unexplained weight loss).
If you do have symptoms, one test of 48 mmol/mol or above is sufficient for diagnosis.
Certain conditions can affect HbA1c accuracy, including haemoglobin variants (e.g. sickle cell trait), iron deficiency anaemia, recent blood loss, and chronic kidney disease. If any of these apply to you, your doctor may use an alternative test such as a fasting plasma glucose or oral glucose tolerance test.
A result of 48 is often described as "newly diagnosed" or "early-stage" type 2 diabetes. Because it sits at the lower end of the diabetic range, many people are offered an intensive lifestyle programme before medication is prescribed.
If your HbA1c is between 42 and 47 (pre-diabetes) or newly diagnosed at 48, your GP may refer you to the NHS Diabetes Prevention Programme. This is a free, evidence-based programme that has been shown to reduce HbA1c significantly through structured diet and exercise advice.
For an HbA1c of 48, your GP may recommend a 3-to-6 month trial of lifestyle changes before starting medication. If the HbA1c remains at or above 48 mmol/mol despite lifestyle efforts, metformin is typically the first medication offered in the UK. Metformin is well-tolerated, safe, inexpensive, and has decades of evidence behind it.
Once diagnosed, your HbA1c will typically be checked every 3 months initially, then every 6 months once stable. The NHS target for most people with type 2 diabetes is an HbA1c below 48 mmol/mol (i.e. back into or near the normal range).
Reducing carbohydrate intake — especially refined carbohydrates like white bread, rice, pasta, sugary drinks, and biscuits — can lower HbA1c significantly. The DIRECT trial (published in the Lancet) demonstrated that a very-low-calorie diet (around 800 calories per day for 12 weeks) put nearly 50% of participants into remission. A Mediterranean-style diet and a low-carbohydrate diet are both supported by evidence.
Exercise makes your muscles more sensitive to insulin. NICE recommends at least 150 minutes of moderate-intensity activity per week (such as brisk walking, cycling, or swimming). Even a 20-minute walk after meals can noticeably reduce blood sugar spikes.
For people who are overweight, weight loss is the single most effective intervention. Losing 10–15% of body weight (e.g. 10–15 kg for a 100 kg person) can achieve remission in many cases of early type 2 diabetes.
Swap white bread for wholegrain or seeded bread. Replace sugary drinks with water or unsweetened tea. Eat more vegetables, legumes, and lean protein. Avoid ultra-processed foods. Aim for consistent sleep, as poor sleep independently raises blood sugar.
Yes and no. The threshold of 48 is a clinical cut-off, not a cliff edge — there is no fundamental biological difference between 47 and 48. However, a higher HbA1c does indicate a greater degree of blood sugar elevation and may influence how quickly your GP wants to start treatment. An HbA1c of 55 or 60 would be more likely to prompt early medication, whereas 48 typically allows time for a lifestyle trial first.
Contact your GP promptly if you experience any of the following alongside an elevated HbA1c: extreme thirst, passing large amounts of urine (especially at night), unexplained weight loss, blurred vision, tiredness, or recurring infections. These are the classic symptoms of uncontrolled diabetes and require prompt assessment.
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