Diabetes screening HbA1c
Informed by recognized medical guidance
Overview
HbA1c is a simple blood test that measures your average blood sugar level over the past 2 to 3 months. It is used to screen for diabetes and prediabetes (higher than normal blood sugar that is not yet diabetes).
Key facts
- HbA1c stands for glycated haemoglobin – it shows how much sugar has attached to your red blood cells.
- A normal HbA1c level is below 42 mmol/mol (or 6.0%). Levels between 42 and 47 mmol/mol (6.0% to 6.4%) suggest prediabetes, and levels of 48 mmol/mol (6.5%) or higher indicate diabetes.
- The test does not require fasting, so it is convenient for routine screening.
Yes, diabetes is very common. In the UK, about 1 in 10 adults has some form of diabetes, and many people have prediabetes without knowing it.
It can affect anyone, but it is more common in adults over 40, people who are overweight, those with a family history of diabetes, and certain ethnic groups (including South Asian, Black African, and Caribbean communities).
Symptoms
- Very high blood sugar – feeling weak, confused, breathing fast, or fruity-smelling breath (signs of diabetic ketoacidosis, a medical emergency)
- Loss of consciousness or seizures
- ⚠Blood sugar that stays very high (usually above 15 mmol/L) despite your usual plan
- ⚠Repeated vomiting or diarrhoea that prevents you from keeping fluids down
- ⚠Signs of infection with high fever and feeling very unwell
Common symptoms
- Frequent urination, especially at night
- Feeling very thirsty all the time
- Unexplained weight loss
- Fatigue and lack of energy
- Blurred vision
- Slow healing of cuts or infections
Symptoms in children
- Bedwetting in a child who previously did not wet the bed
- Extreme thirst
- Weight loss despite normal or increased appetite
- Irritability or mood changes
Symptoms in older adults
- Feeling confused or unusually tired
- More frequent infections, for example urinary tract infections
- Unexplained weight loss
- Poor wound healing
Causes
Main causes
- Insulin resistance – when your body’s cells do not respond well to insulin (the hormone that controls blood sugar)
- Not enough insulin production from the pancreas
- In type 1 diabetes, the immune system attacks the insulin-producing cells; in type 2 diabetes, lifestyle and genetics play a larger role.
Risk factors
- Being overweight or obese, especially with fat around the belly
- Having a close family member (parent, sibling) with type 2 diabetes
- Being over 40 (or over 25 if you are from a high-risk ethnic group)
- High blood pressure, high cholesterol, or heart disease
- Having had gestational diabetes during pregnancy
- Not being physically active enough
When to see a doctor
See a doctor urgently if:
- If you have symptoms of very high blood sugar (confusion, rapid breathing, fruity-smelling breath) – call emergency services immediately
- If you have blood sugar readings that are very high (above 15 mmol/L) and you feel very unwell
Book a routine appointment if:
- If you are over 40 and have not been screened for diabetes in the last 3 years
- If you have one or more risk factors (family history, overweight, high blood pressure) – ask your GP about a simple blood test
- If you notice any symptoms of diabetes listed above, even if mild
Diagnosis
A diagnosis of diabetes or prediabetes is made through blood tests. The main screening test is the HbA1c, which does not require fasting. Your doctor may also use a fasting blood glucose test or an oral glucose tolerance test (drinking a sugary drink and measuring blood sugar afterwards).
Tests that may be done
- HbA1c blood test – measures average blood sugar over 2–3 months
- Fasting blood glucose test – your blood sugar level after not eating for at least 8 hours
- Oral glucose tolerance test (OGTT) – blood sugar measured before and 2 hours after a sugary drink
What to expect at your appointment
Your doctor or nurse will take a small blood sample from your arm. There is no special preparation for the HbA1c test – you can eat and drink normally. Results usually come back within a few days. The doctor will explain what your result means and what steps to take next.
Treatment
Treatment for diabetes aims to keep your blood sugar as close to normal as possible. For prediabetes, lifestyle changes can often reverse it or prevent type 2 diabetes. For diabetes, a combination of healthy eating, physical activity, and sometimes medication is used.
Self-care at home
- Follow a balanced diet rich in vegetables, whole grains, lean protein, and healthy fats – limit sugary drinks and refined carbohydrates
- Be physically active most days – aim for at least 150 minutes of moderate exercise per week (like brisk walking, cycling, or swimming)
- Monitor your blood sugar levels if your doctor advises it – keep a record and share with your healthcare team
- Take any prescribed medication exactly as directed – do not skip doses or change amounts without talking to your doctor
Medical treatments
If lifestyle changes are not enough, your doctor may prescribe medication to help control blood sugar. Several types of tablets are available, and some people may need insulin injections. The choice depends on the type of diabetes, your blood sugar levels, and your overall health. Your healthcare team will work with you to find the best plan.
When is surgery considered?
Surgery is not a standard treatment for diabetes itself. However, for some people with type 2 diabetes and severe obesity, bariatric surgery (weight-loss surgery) can improve blood sugar control and even lead to remission. This option is discussed only when other treatments have not worked and after careful medical assessment.
Living with this condition
Living with diabetes means being aware of your blood sugar levels, but most people can lead a full, active life. You will need to check your blood sugar regularly, take medication as needed, and plan meals and exercise carefully. Over time, these steps become routine.
Lifestyle tips
- Keep a regular schedule for meals and snacks to avoid blood sugar spikes or drops
- Check your feet every day for cuts, blisters, or sores – diabetes can reduce healing and foot sensation
- See your doctor for regular eye checks, foot exams, and blood tests (including HbA1c) every 3 to 6 months
- Carry a source of fast sugar (like glucose tablets or fruit juice) in case your blood sugar drops too low
Diet and exercise
A healthy diet helps control blood sugar. Focus on fibre-rich foods (oats, beans, lentils), non-starchy vegetables, and lean proteins. Limit sugary snacks and white bread. Exercise lowers blood sugar by helping your cells use glucose better. Even a 20-minute walk after meals can make a difference.
Mental health and emotional wellbeing
Living with diabetes can be stressful. It is common to feel worried, frustrated, or burned out by the constant monitoring. Talk to your doctor or a counsellor if you feel overwhelmed. Support from family, friends, or a diabetes support group can also help.
Prevention
Type 1 diabetes cannot be prevented, but type 2 diabetes and prediabetes can often be prevented or delayed with lifestyle changes. Maintaining a healthy weight, staying physically active, and eating a balanced diet are the most effective steps.
Screening programmes
Routine screening for diabetes is not necessary for everyone, but it is recommended if you have risk factors (such as being over 40, overweight, or having a family history). Your doctor can advise on when to start and how often to get tested.
Complications
If left untreated
- Heart disease and stroke
- Kidney disease (nephropathy) that may lead to kidney failure
- Nerve damage (neuropathy) causing numbness, pain, or digestive issues
- Eye problems (retinopathy) that can lead to blindness
- Foot infections and ulcers that may require amputation
Long-term outlook
The outlook for people with diabetes is very good when it is managed well. Many people live long, healthy lives with few complications. Early detection through HbA1c screening gives you the best chance to stay well. With proper care and support, you can reduce your risk of serious problems.
Find support
International organisations
Local organisations
- Diabetes UK ↗ · United Kingdom
- National Health Service (NHS) – Diabetes ↗ · United Kingdom
External links open third-party websites. Ruqelo Health is not responsible for external content. Listing an organisation does not imply endorsement.
Always verify with your doctor
Health guidelines vary by country and region. The information in this article is based on international clinical guidelines but may not reflect the specific guidelines, medications, or practices in your country. Always discuss your health concerns with your own doctor or healthcare provider, and refer to your local national health guidelines where available.
Important notice This information is for educational purposes only. It does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your specific situation. If you are experiencing a medical emergency, call your local emergency services immediately.
Related conditions
Sources and guidance
This article is educational and is prepared with reference to recognized health information and clinical guidance sources where available. Specific source links may vary by topic.
Last updated: July 19, 2026
Educational note: This information is for education only and is not a diagnosis.
Use it to support, not replace, advice from a licensed clinician.
If symptoms are severe, worsening, or urgent, call your local emergency number or seek emergency care.