How to Know If You Have Prediabetes: The Silent Warning Sign You Can’t Afford to Ignore

               

Prediabetes is often called the “silent” condition—and for good reason. According to Diabetes UK, around one in five people in the UK are living with prediabetes, yet the vast majority have no idea. That’s the thing about learning how to know if you have prediabetes: it rarely announces itself with obvious symptoms. Instead, it quietly raises your blood sugar levels above normal without crossing the threshold into type 2 diabetes, all while increasing your risk of serious health complications down the line.

             

What Exactly Is Prediabetes?

Before we dive into how to know if you have prediabetes, let’s clarify what it actually means. Prediabetes—also known as non-diabetic hyperglycemia or impaired glucose tolerance—occurs when your blood glucose levels are higher than normal but not yet high enough to be classified as type 2 diabetes.

Think of it as a warning light on your body’s dashboard. It doesn’t mean you have diabetes, but it does mean you’re on the path towards it unless you take action. The good news? Prediabetes is reversible. With the right lifestyle changes, you can bring your blood sugar back into a healthy range and significantly reduce your risk of developing type 2 diabetes. That’s why understanding how to know if you have prediabetes is so crucial—it gives you the opportunity to intervene early. 

         

The Challenge: Why Prediabetes Often Goes Undetected

One of the biggest obstacles in how to know if you have prediabetes is that the condition typically has no symptoms. Unlike type 2 diabetes, which can cause noticeable issues like extreme thirst and frequent urination, prediabetes often flies under the radar for years.

Many people only discover they have prediabetes during a routine blood test or an NHS Health Check. This is precisely why being proactive about your health is so important. If you’re waiting for symptoms to appear, you could be waiting a long time—and by then, the condition may have already progressed.

Warning Signs That Might Indicate It’s Time to Get Tested

While prediabetes itself is usually symptomless, some people do experience subtle signs that shouldn’t be ignored. These can include:

• Increased thirst and frequent urination – High blood sugar can lead to dehydration and more trips to the toilet.
• Unexplained fatigue – If your body isn’t using glucose effectively for energy, you may feel more tired than usual.
• Blurred vision – Temporary swelling of the eye’s lens can occur when blood sugar is elevated.
• Slow-healing cuts and frequent infections – High glucose levels can impair circulation and weaken the immune system.
• Darkened skin patches—Velvety, dark areas on the neck, armpits, or groin (known as acanthosis nigricans) can be a sign of insulin resistance.
• Numbness or tingling – Nerve damage from high blood sugar can cause tingling in the hands or feet.

If you’re experiencing any of these, it’s a strong indication that how to know if you have prediabetes should be a priority. Book an appointment with your GP and ask for a blood test.

Who Is Most at Risk?

Knowing how to know if you have prediabetes also means understanding your personal risk factors. Some people are more likely to develop the condition than others. According to NHS guidance, you should be particularly vigilant if you:

• Are over 40 (or over 25 if you’re of African-Caribbean, Black African, South Asian, or Chinese descent)
• Have a parent or sibling with type 2 diabetes
• Are overweight or obese
• Have high blood pressure or high cholesterol
• Have a history of gestational diabetes
• Have polycystic ovary syndrome (PCOS)
• Are physically active less than three times a week

The more of these risk factors you have, the more important it becomes to understand how to know if you have prediabetes and take action.

The Blood Tests That Tell You for Certain

So, how to know if you have prediabetes with certainty? The answer lies in a simple blood test. The most common test used by the NHS is the HbA1c test, which measures your average blood sugar levels over the past two to three months.

Here’s what the results mean:

• Normal: HbA1c below 42 mmol/mol
• Prediabetes: HbA1c between 42 and 47 mmol/mol
• Diabetes: HbA1c of 48 mmol/mol or above

Some GPs may also use a fasting plasma glucose test (where you fast overnight before having your blood taken) or an oral glucose tolerance test (which involves drinking a sugary solution and having your blood checked two hours later). But for most people, the HbA1c test is the standard approach.

If your results fall into the prediabetes range, you now have the answer to how to know if you have prediabetes – and more importantly, you have the power to do something about it.     

What to Do If You Find Out You Have Prediabetes

Receiving a prediabetes diagnosis can feel worrying, but it’s also an opportunity. Knowing how to know if you have prediabetes is only the first step; the next is taking control.

Research shows that lifestyle changes can reduce the risk of developing type 2 diabetes by around 50% and may even reverse prediabetes altogether. The NHS recommends:

• Losing 5–10% of your body weight—even moderate weight loss can make a significant difference
• Increasing physical activity – aim for at least 150 minutes of moderate-intensity exercise per week, such as brisk walking, swimming, or cycling
• Adopting a balanced diet – focus on whole grains, lean proteins, fruits, and vegetables, while limiting processed foods and sugary drinks
• Reducing carbohydrate and sugar intake – opt for complex carbohydrates like brown rice and wholemeal bread over refined options

The NHS Diabetes Prevention Programme (also known as Healthier You) is a free, evidence-based programme available to those at high risk. It offers practical support with healthy eating, physical activity, and weight management. Ask your GP about a referral if you’re eligible.

             

A Useful Resource to Help You on Your Journey

If you’re serious about understanding how to know if you have prediabetes and what to do next, there are excellent resources available to guide you. For a comprehensive overview of prediabetes, including detailed guidance on testing, risk factors, and lifestyle strategies, you may find it helpful to explore this useful resource. It brings together reliable information in one place, making it easier to take the next steps with confidence. 

Frequently Asked Questions

Q: Can I have prediabetes without any symptoms?

Yes. In fact, most people with prediabetes have no symptoms at all. That’s why understanding how to know if you have prediabetes usually requires a blood test rather than waiting for signs to appear.

Q: How is prediabetes diagnosed in the UK?

The NHS typically uses an HbA1c blood test. A result between 42 and 47 mmol/mol indicates prediabetes. Your GP may also use a fasting glucose test or an oral glucose tolerance test.

Q: Can prediabetes be reversed?

Yes. With lifestyle changes – including weight loss, healthier eating, and regular exercise – many people can bring their blood sugar levels back into the normal range.

Q: How long does it take for prediabetes to become type 2 diabetes?

Without intervention, it can occur within five years, though this varies depending on factors like age, genetics, and lifestyle. Early action is key.

Q: Should I see my GP if I think I might have prediabetes?

Absolutely. If you have any risk factors or are experiencing symptoms, booking a blood test with your GP is the only way to know for certain.

Final Thoughts

Understanding how to know if you have prediabetes could be one of the most important health decisions you make. The condition is common, often invisible, but entirely manageable – and in many cases, reversible. By knowing your risk factors, paying attention to subtle warning signs, and getting tested, you give yourself the best possible chance to prevent type 2 diabetes before it develops.

Don’t wait for symptoms to appear. Speak to your GP, ask about a blood test, and take the first step towards a healthier future today. For more detailed information and guidance, click here to access a helpful resource that can support you on your journey.

Your health is in your hands – and knowing how to know if you have prediabetes is where it all begins.