Prediabetes — also called non-diabetic hyperglycaemia or being at high risk of type 2 diabetes — means your blood glucose levels are above the normal range but have not reached the threshold used to diagnose diabetes.
In the UK, an HbA1c result between 42 and 47 mmol/mol is generally considered to indicate a high risk of developing type 2 diabetes. An HbA1c of 48 mmol/mol or above may indicate diabetes and normally requires appropriate clinical confirmation when the person does not have symptoms.
Prediabetes does not mean that you are guaranteed to develop type 2 diabetes, but it does indicate that you are at much higher risk compared to someone with lower blood sugar levels.
NICE specifically advises that people at high risk should make lifestyle changes involving physical activity, diet, weight where relevant to reduce their risk of developing type 2 diabetes.
At our private clinic in Edgbaston, Birmingham, we can assess diabetes risk, arrange HbA1c and personalised blood testing, review your wider metabolic and cardiovascular health and help you create a realistic plan based on your individual results.
This guide explains what prediabetes means, who is at higher risk, how testing works and what we would usually consider after an abnormal result.
Key Takeaways
Prediabetes means your blood glucose is higher than normal but has not reached the diagnostic threshold for diabetes.
In UK guidance, an HbA1c of 42–47 mmol/mol is considered high risk for type 2 diabetes.
An HbA1c of 48 mmol/mol or above may indicate diabetes and usually requires appropriate confirmation if you do not have symptoms.
Prediabetes usually causes no obvious symptoms.
You can develop prediabetes even if you are not overweight.
Risk is influenced by factors including age, family history, ethnicity, weight, waist measurement, blood pressure and previous gestational diabetes.
HbA1c reflects average blood glucose over approximately the previous two to three months.
HbA1c testing usually does not require fasting.
Prediabetes does not mean that type 2 diabetes is inevitable.
NICE recommends structured lifestyle support for people confirmed to be at high risk.
People at high risk should generally have their blood glucose risk reassessed at least annually.
Medication such as metformin may occasionally be considered for selected high-risk patients, but lifestyle intervention remains central.
At our clinic, HbA1c testing can form part of a personalised blood test or wider health assessment.
What Is Prediabetes?
Prediabetes is a term used when blood glucose has risen above the expected range but is not high enough to meet the diagnostic criteria for diabetes.
Healthcare professionals may also use terms such as:
Non-diabetic hyperglycaemia
Impaired glucose regulation
High risk of type 2 diabetes
They broadly describe the same underlying concern:
Your body is beginning to have more difficulty maintaining normal blood-glucose levels.
Diabetes UK currently describes prediabetes as an HbA1c level between 42 and 47 mmol/mol, with type 2 diabetes diagnosed from 48 mmol/mol or above when appropriate diagnostic criteria are met.
What Does an HbA1c Result Mean?
One of the main tests used to assess diabetes risk is HbA1c.
The result is normally given in mmol/mol. A reading below 42 mmol/mol is below the prediabetes range.That does not necessarily mean your future diabetes risk is zero, your age, family history, ethnicity, weight and other health factors may still matter.
A reading between 42–47 mmol/mol is considered high risk of type 2 diabetes, often referred to as prediabetes or non-diabetic hyperglycaemia.
A reading of 48 mmol/mol or above is within the range considered to be diabetic. If you receive test results with hba1c within this range, it does not automatically mean that you will be diagnosed with diabetes. If you have no symptoms, an abnormal diagnostic result normally needs confirmation with another appropriate blood test before a diagnosis is made.
Does Prediabetes Cause Symptoms?
No, not always.
Diabetes UK states that people with prediabetes generally do not have symptoms. That means you can feel completely healthy while your blood glucose is gradually increasing.
Prediabetes is often discovered during:
Routine blood testing
A health MOT
Cardiovascular screening
Weight-management assessment
Investigation of another health problem
Diabetes-risk screening
What About Thirst and Frequent Urination?
Symptoms such as:
Increased thirst
Frequent urination
Unexplained weight loss
Significant tiredness
Blurred vision
are more strongly associated with higher blood glucose and diabetes rather than uncomplicated prediabetes.
The NHS lists increased thirst, frequent urination, tiredness and unexplained weight loss among the common symptoms of type 2 diabetes.
If you have symptoms like these, do not assume:
"It is probably only prediabetes."
You should arrange appropriate medical assessment and blood testing.
Who Is at Risk of Prediabetes?
Type 2 diabetes develops through a combination of factors.
Age
Risk tends to increase with age.
The NHS highlights increased type 2 diabetes risk from around:
40 years old in white adults
25 years old in adults from South Asian, Chinese, Black African or Black Caribbean backgrounds
although younger people can also develop type 2 diabetes.
Family History
Having a close relative with type 2 diabetes increases your risk.
This includes:
Parent
Brother
Sister
Child
Diabetes UK reports that people with a close family history can have around two to six times the risk of developing type 2 diabetes compared with someone without that family history.
You cannot change your genetics, but knowing your family history may influence how proactively we monitor your metabolic health.
Ethnicity
Type 2 diabetes risk is higher in several ethnic groups.
Diabetes UK reports higher risk among people of:
South Asian heritage
African-Caribbean heritage
Black African heritage
and notes that type 2 diabetes can also develop at a younger age in these groups.
Weight
Living with overweight or obesity increases the risk of type 2 diabetes.
However, weight is not the only factor.
People within a healthy BMI range can still develop prediabetes.
Waist Measurement
Where body fat is carried can also matter.
A higher waist measurement is associated with increased metabolic risk.
High Blood Pressure
High blood pressure is another important risk factor and often overlaps with other cardiovascular and metabolic risks.
Previous Gestational Diabetes
Women who previously developed diabetes during pregnancy have an increased future risk of type 2 diabetes and may require ongoing monitoring.
Other Factors
Risk can also be influenced by:
Low physical activity
Certain medications
Polycystic ovary syndrome
Previous abnormal blood glucose
Cardiovascular disease
Other metabolic conditions
Your risk profile is built from several pieces rather than one isolated factor.
Does Being Overweight Cause Prediabetes?
No, not by itself. Being overweight does not necessarily mean that you have prediabetes or are guaranteed to develop prediabetes.
Diabetes UK explicitly notes that although prediabetes is more common in people who are medically overweight or obese, it can also affect people at a healthy weight.
Type 2 diabetes develops through interaction between:
Genetics
Insulin resistance
Pancreatic function
Age
Body composition
Activity
Diet
Other health factors
Weight can be important.
But it is not the entire explanation.
Why Weight Still Comes Up
For someone living above a healthy weight, modest and sustainable weight reduction can significantly improve metabolic health.
NICE advises people who are overweight or living with obesity and at high risk of type 2 diabetes to consider gradual weight reduction and describes 5–10% of body weight over one year as a realistic initial target associated with meaningful health benefits.
That does not mean everyone with prediabetes needs to lose 10%.
Some people do not need to lose weight at all.
The plan should reflect the individual.
How Is Prediabetes Tested?
The most commonly used tests include:
HbA1c
This reflects average blood glucose over approximately the previous two to three months.
Fasting Plasma Glucose
This measures the glucose level in your blood after fasting.
NICE considers a fasting plasma glucose of 5.5–6.9 mmol/L to represent high diabetes risk within its prevention guidance.
Oral Glucose Tolerance Test
An OGTT involves measuring blood glucose before and after consuming a glucose drink.
This can provide additional information about how your body processes glucose.
It is used in selected situations rather than automatically being required for everybody.
Which Test Do You Need?
For many adults being assessed for type 2 diabetes risk, HbA1c is convenient and informative.
But there are circumstances where HbA1c may be unreliable or inappropriate.
These can include conditions affecting:
Red blood cell lifespan
Certain haemoglobin variants
Significant anaemia
Some kidney or liver conditions
Rapidly changing blood glucose
An NHS laboratory guide specifically notes that altered red-cell turnover and some medical conditions can distort the relationship between HbA1c and actual glucose levels.
That is why blood-test results still need clinical interpretation.
What Is an HbA1c Test?
HbA1c stands for glycated haemoglobin.
Glucose circulates in your bloodstream.
Some of it attaches to haemoglobin within red blood cells.
The higher your average blood glucose has been, the more glycated haemoglobin tends to be present.
Because red blood cells remain in circulation for several months, HbA1c provides a longer-term view of blood glucose rather than a single snapshot.
Our own diabetes education article describes HbA1c as reflecting average blood glucose over approximately the previous two to three months.
HbA1c vs a Finger-Prick Test
A finger-prick glucose reading tells you what your blood sugar is doing at that particular moment.
HbA1c measures the average glucose levels over the past 2-3 months by looking at how sugar molecules have bound to the red blood cells.
Do You Need to Fast for an HbA1c Test?
No. An advantage of the HbA1c test is that it can usually be taken at any time of day without fasting.
NICE specifically notes that HbA1c does not require the special fasting preparation needed for some other glucose tests.
You can normally:
Eat
Drink
Take your usual routine
before the blood test unless you are having other blood markers at the same appointment that require different preparation. For example, if your HbA1c is part of a wider personalised health profile, your clinician may give you specific instructions based on the other tests being performed.
What Happens If Your HbA1c Is 42–47?
First:
Do not panic.
An HbA1c between 42 and 47 mmol/mol does not mean you currently have type 2 diabetes.
It means your risk is higher.
NICE recommends that people confirmed to be at high risk should be told clearly that progression to diabetes is not inevitable and that risk can be reduced.
The next step should be understanding your individual risk profile.
We may consider:
Age
Weight and waist measurement
Blood pressure
Family history
Ethnicity
Cholesterol
Smoking
Physical activity
Diet
Existing medical conditions
Medication
From there, we can decide what changes are most relevant.
You May Be Offered Structured Support
NICE recommends referral to an evidence-based intensive lifestyle-change programme for people confirmed to be at high risk.
The NHS also has diabetes-prevention services designed specifically for people at high risk of developing type 2 diabetes.
Private care can work alongside these services rather than replacing them.
Can Prediabetes Be Reversed?
You might see claims online saying that someone has "reversed prediabetes." What this usually means is that their blood glucose has fallen back below the prediabetes threshold.
Diabetes UK states that health changes can sometimes return HbA1c from the prediabetes range to below 42 mmol/mol.
That is clearly a positive outcome, but it does not necessarily mean that your underlying future risk has disappeared forever. If the factors that contributed to the raised HbA1c return, blood glucose may rise again.
What Lifestyle Changes Can Reduce Diabetes Risk?
There is no single "prediabetes diet." The most useful changes are the ones you can actually maintain.
NICE recommends intensive lifestyle programmes focused on areas including:
Physical activity
Weight management where appropriate
Higher-fibre foods
Wholegrains
Vegetables
Reducing saturated fat
Sustainable behaviour change
rather than short-term extreme diets.
Diet
A useful starting point may include:
More vegetables
More high-fibre foods
Wholegrain carbohydrates where appropriate
Adequate protein
Reducing frequent sugary drinks
Reducing heavily processed foods
Paying attention to portion size
Choosing dietary changes that you can realistically continue
Avoid the Crash-Diet Cycle
A highly restrictive diet may produce rapid short-term changes but become impossible to maintain. Prediabetes management is a long-term project, so finding a diet that you can maintain and that lowers your Hba1c is ideal. You don’t need to conquer everything all at once.
Do You Need to Lose Weight?
Treatment for prediabetes do not focus purely on weight loss but put more attention on your diet and lifestyle habits. Changing your diet in order to lower your Hba1c may cause weight loss, but this is a bi-product of the treatment and not the main goal.
Can I lose weight and manage my pre-diabetes at the same time?
Yes. At our clinic, we can also provide GP-led medical weight management alongside pre-diabetes treatment where medically appropriate.
Not everyone with prediabetes needs weight-loss treatment, but if weight is one significant part of your metabolic risk and you would like structured support, we can consider:
Health assessment
Realistic goal setting
Lifestyle changes
Behaviour support
Medical treatment where clinically appropriate
Ongoing monitoring
Our wider weight-management service is designed around the individual rather than simply targeting a number on the scales.
Does Exercise Help Prediabetes?
Yes.Physical activity is one of the major tools available for reducing type 2 diabetes risk, exercise can improve the way your body responds to insulin and help muscles use glucose.
NICE recommends increasing physical activity as a core part of diabetes-prevention programmes.
Useful activity can include:
Walking
Cycling
Swimming
Dancing
Strength training
Gym sessions
Sport
Other movement you enjoy
Strength Training Can Be Useful Too
Muscle tissue plays an important role in glucose metabolism, so resistance exercise can be a great addition to your activity/exercise plan.
The best programme is generally one that:
Fits your current fitness
Is safe for your health
Is realistic around your schedule
Can gradually progress
If you currently do almost no activity, starting with manageable increases is usually more useful than designing a perfect six-day training programme that lasts one week.
Do You Need Medication for Prediabetes?
Usually, lifestyle intervention is the starting point.
Most people with prediabetes are not automatically prescribed medication.
However, there are circumstances where medication may be considered.
Metformin
NICE advises clinicians to consider metformin for selected people at high risk when:
Blood glucose has continued to worsen despite participation in an intensive lifestyle-change programme, or
The person cannot participate in such a programme
particularly where BMI is over 35 kg/m².
NICE also emphasises that long-term lifestyle change can be more effective than medication in preventing or delaying type 2 diabetes and recommends that lifestyle support continues even if metformin is prescribed.
Medication Is Not a Substitute for Understanding Risk
If medication is considered, we still need to understand:
Weight
Diet
Physical activity
Blood pressure
Cholesterol
Smoking
Sleep
Other metabolic health factors
How Often Should HbA1c Be Repeated?
This depends on your level of risk.
For people confirmed to be at high risk with an HbA1c between 42 and 47 mmol/mol, NICE recommends a blood test at least once a year. For those with poorly controlled diabetes, test every 6 or even every 3 months may be recommended.
NICE also recommends annual review of lifestyle changes and relevant risk factors.
What If Your HbA1c Is 48 or Above?
An HbA1c of 48 mmol/mol or above falls within the diagnostic range for diabetes.
If you have no symptoms, NICE recommends a second blood test to confirm possible type 2 diabetes.
What If You Have Diabetes Symptoms?
The NHS lists these among the common symptoms of type 2 diabetes:
Persistent thirst
Urinating much more than usual
Unexplained weight loss
Marked tiredness
Blurred vision
Slow-healing wounds
Recurrent thrush
If you begin to experience any of these symptoms, you should seek medical assessment rather than simply waiting for your next annual health check.
Type 1 Diabetes Can Also Occur in Adults
Not every person with high blood glucose has type 2 diabetes.
Type 1 diabetes can develop in adulthood as well as childhood.
Symptoms that develop rapidly — particularly significant thirst, frequent urination, rapid weight loss or feeling very unwell — need prompt medical assessment.
HbA1c is not always the appropriate test when blood glucose may have risen rapidly.
If you become acutely unwell, seek urgent medical advice rather than relying on a routine prediabetes appointment.
What Other Health Checks May Be Useful?
Prediabetes rarely deserves to be looked at completely on its own, many of the same factors that increase diabetes risk also influence cardiovascular health.
A wider assessment may therefore include:
Blood Pressure
High blood pressure commonly overlaps with metabolic risk.
Cholesterol
A lipid profile may include:
Total cholesterol
LDL
HDL
Non-HDL cholesterol
Triglycerides
Weight and Waist Measurement
These can provide useful information when interpreted alongside other health factors.
Kidney Function
Kidney-health markers may be relevant depending on your medical history and wider metabolic health.
Liver Function
Metabolic health can overlap with conditions affecting the liver.
Medication Review
Certain medicines can affect blood glucose.
For example, corticosteroid medication can sometimes increase blood sugar.
Lifestyle Review
We may also discuss:
Physical activity
Nutrition
Alcohol
Smoking
Sleep
Stress
The objective is to understand your overall risk, not simply move one blood-test number below a particular line.
Prediabetes Testing at Our Birmingham Clinic
Our clinic is based at:
38 Harborne Road
Edgbaston
Birmingham
B15 3EB
We provide private GP care, personalised blood testing, preventative health assessments, weight management and health coaching for patients across Birmingham and the surrounding West Midlands.
If you are concerned about prediabetes, we can help at several different stages.
You Want to Know Your Diabetes Risk
Perhaps:
Diabetes runs in your family
You have gained weight
You previously had gestational diabetes
You have high blood pressure
You have never had your HbA1c checked
You simply want a preventative health review
We can discuss your risk profile and arrange appropriate blood testing.
You Already Have an HbA1c Result
Maybe you have been told:
"Your HbA1c is 44."
but do not really understand what that means.
We can review:
The result
Previous measurements
Your risk factors
Wider metabolic health
Whether another test is needed
What changes may be useful
You Have Been Told You Have Prediabetes
If your HbA1c sits within the high-risk range, our focus is on what happens next.
That may include:
Lifestyle planning
Weight management where appropriate
Physical activity
Nutrition
Blood pressure
Cholesterol
Repeat blood testing
Ongoing GP monitoring
Health coaching
You Are Worried You May Already Have Diabetes
If symptoms or blood results suggest possible diabetes, we can assess you and arrange appropriate follow-up testing.
HbA1c can be included within our personalised blood-testing service.
Our personalised testing currently works on a:
£120 phlebotomy and analysis fee
plus
the cost of the selected biomarkers.
We provide a quote before arranging the blood draw.
HbA1c is also included within broader metabolic and preventative-health profiles where appropriate.
Full Health MOT
For patients who want a broader picture of their health, our current Full Health MOT costs £279 and includes metabolic and cardiovascular markers alongside liver, kidney, thyroid and other health measures.
A broad profile is not necessary for everybody.
If all we need to answer the question is a smaller group of tests, we would rather recommend the relevant tests than simply order the biggest panel.
What Happens After Testing?
Once your results are available, we review them in the context of:
Symptoms
Medical history
Medication
Previous results
Lifestyle
Wider health information
We can then discuss whether the appropriate next step is:
Reassurance
Lifestyle change
Repeat testing
Monitoring
Weight-management support
Medication where appropriate
Further investigation
Ongoing diabetes care
Our personalised blood-testing pathway includes follow-up discussion of abnormal or borderline results rather than simply sending you a laboratory report without explanation.
Frequently Asked Questions
What is prediabetes?
Prediabetes means your blood glucose is higher than the normal range but has not reached the level used to diagnose diabetes. It is also known as non-diabetic hyperglycaemia or being at high risk of type 2 diabetes.
What HbA1c level is prediabetes?
In UK guidance, an HbA1c of 42–47 mmol/mol is considered high risk for type 2 diabetes.
What HbA1c level means diabetes?
An HbA1c of 48 mmol/mol or above may indicate diabetes. In someone without symptoms, a second blood test is normally used to confirm the diagnosis.
Is 42 HbA1c prediabetes?
Yes. An HbA1c of 42 mmol/mol falls at the lower end of the UK high-risk or prediabetes range.
Is 47 HbA1c diabetes?
An HbA1c of 47 mmol/mol remains within the high-risk or prediabetes range. A result of 48 mmol/mol or above reaches the diagnostic threshold used for diabetes, subject to appropriate clinical confirmation.
Does prediabetes have symptoms?
Usually not. Diabetes UK states that most people with prediabetes do not experience symptoms. This is why blood testing is often how it is discovered.
Can prediabetes turn into type 2 diabetes?
Yes. Prediabetes means your risk of developing type 2 diabetes is increased. However, progression is not inevitable and risk can often be reduced through sustained changes to health and lifestyle.
Can prediabetes go back to normal?
Yes. Some people can bring HbA1c back below 42 mmol/mol through health and lifestyle changes. This does not necessarily mean all future diabetes risk has disappeared, so ongoing monitoring may still be appropriate.
Do you need to lose weight if you have prediabetes?
Not necessarily. People of a healthy weight can develop prediabetes. If you are overweight or living with obesity, gradual weight reduction may help reduce diabetes risk. NICE describes 5–10% weight loss over a year as a realistic initial goal for people who would benefit from weight reduction.
Can thin people get prediabetes?
Yes. Weight is only one risk factor. Genetics, family history, ethnicity, age and other metabolic factors can also influence diabetes risk.
Does prediabetes mean I need medication?
Usually not automatically. Lifestyle intervention is central to prediabetes management. NICE advises considering metformin for selected high-risk patients whose blood glucose continues to deteriorate despite intensive lifestyle intervention or who cannot participate in such a programme, particularly where BMI is above 35.
Do I need to fast for an HbA1c test?
No. HbA1c can normally be measured without fasting. If you are having additional blood tests at the same appointment, we will tell you if any of those require special preparation.
What does an HbA1c test measure?
HbA1c reflects average blood glucose over roughly the previous two to three months rather than your blood sugar at one particular moment.
How often should HbA1c be checked if I have prediabetes?
NICE recommends that people confirmed to be at high risk of type 2 diabetes have their blood glucose reassessed at least annually, with more frequent monitoring when clinically appropriate.
What are the main risk factors for type 2 diabetes?
Important factors include age, family history, ethnicity, overweight or obesity, higher waist measurement, high blood pressure, previous abnormal glucose levels and several other metabolic or medical conditions.
Can exercise lower diabetes risk?
Yes. Increasing physical activity is a central part of NICE's recommendations for reducing type 2 diabetes risk. The most appropriate activity plan depends on your current health and fitness.
Should I avoid all carbohydrates if I have prediabetes?
No. Prediabetes does not automatically require removing all carbohydrates. A sustainable dietary pattern, portion awareness, higher-fibre foods, wholegrains and reducing excessive intake of heavily processed or sugary foods can form part of a broader plan.
Can I have a private HbA1c test in Birmingham?
Yes. We offer personalised blood testing at our Edgbaston clinic, and HbA1c can be included when assessing diabetes risk or metabolic health.
How much is private blood testing at your clinic?
Our personalised blood-testing service currently has a £120 phlebotomy and analysis fee plus the cost of the biomarkers selected. We confirm the full cost before your blood draw.
Do you offer a broader diabetes health check?
We can assess diabetes risk alongside wider metabolic and cardiovascular health. Our current Full Health MOT costs £279 and includes metabolic and cardiovascular markers alongside other areas such as liver, kidney and thyroid health.
Where is your prediabetes clinic in Birmingham?
Our clinic is located at 38 Harborne Road, Edgbaston, Birmingham, B15 3EB. We provide private GP consultations, personalised blood testing, preventative healthcare, weight management and lifestyle support.
