How to check your blood glucose levels

Blood glucose (or blood sugar) is the main source of energy for your body. It comes from the food you eat, especially carbohydrates, and is transported by the bloodstream to your cells, where it’s used for energy.

Keeping blood glucose within a healthy range is important for overall wellbeing. If levels are too high or too low, it can affect energy, mood and your long-term health. Monitoring your blood glucose can give valuable insight into how your body is processing sugar and may help detect conditions like prediabetes or diabetes earlier.

This article explains how to check your blood glucose levels, what different types of testing involve, and what your results might mean.

Why is it important to check blood glucose levels?

For most people, blood glucose rises after eating and gradually returns to normal as insulin helps move sugar into the body’s cells. If this process doesn’t work properly, blood glucose can remain too high, a key risk factor for type 2 diabetes and other complications.

Because high blood glucose often causes no symptoms in the early stages, many people may not realise they have a problem until it’s more advanced. Regular monitoring can:

• Detect prediabetes or diabetes early

• Show how diet and lifestyle choices affect your blood sugar

• Track how well your body is managing glucose over time

• Help your healthcare provider decide whether further testing or treatment is needed

What are normal blood glucose levels?

Healthy blood glucose targets can vary slightly depending on the test used and whether you’ve eaten recently. As a general guide:

• Fasting blood glucose (before eating): 4.0–5.4 mmol/L (72–99 mg/dL)

• Blood glucose two hours after eating: under 7.8 mmol/L (140 mg/dL)

• Random blood glucose: usually under 7.8 mmol/L (140 mg/dL)

If readings are consistently higher, it may suggest impaired glucose tolerance or diabetes and should be checked by a healthcare professional.

How can you check your blood glucose levels?

There are several ways to measure blood glucose, ranging from simple finger-prick tests at home to more detailed checks in a clinical setting.

Finger-prick testing (capillary blood glucose) This is the most common way to measure blood sugar at home. It involves:

• Using a small lancet to prick the finger

• Applying a drop of blood to a test strip

• Reading the result on a handheld meter

Finger-prick testing gives you a snapshot of your blood glucose at a single moment in time. It’s quick and convenient, but levels can vary depending on when you last ate, so it’s best to follow guidance on when to test.

Continuous glucose monitoring (CGM) A CGM device uses a tiny sensor inserted under the skin to measure glucose in the fluid between your cells. Readings are sent to a monitor or smartphone app, allowing you to see trends over time.

CGMs are often used by people living with type 1 diabetes, but they can also provide detailed insights for others who want to track how their body responds to food, exercise or medication.

Blood glucose testing through a health check Private health assessments or GP blood tests can measure blood glucose directly from a vein. These tests are more accurate and may include additional checks such as:

• Fasting blood glucose – taken after not eating for at least 8 hours

• HbA1c – measures your average blood sugar over the past 2-3 months, giving a more accurate picture of your long-term glucose control than a single reading. Most Bluecrest Wellness health checks include an HbA1c test to help spot early signs of diabetes or prediabetes.

• Oral glucose tolerance test (OGTT) – checks how your body handles sugar after drinking a glucose solution

These types of tests are useful for diagnosing prediabetes or diabetes and for monitoring long-term glucose control.

Can you check blood glucose without a finger prick?

CGM systems offer a needle-free alternative once the sensor is in place, and some use a small patch that can be scanned with a smartphone. However, finger-prick testing is still the most widely available method for quick home checks.

If you don’t want to test at home, booking a private blood test as part of a health check can also give accurate results without the need for daily monitoring.

Do you need to test if you don’t have diabetes?

Even if you haven’t been diagnosed with diabetes, checking your blood glucose may still be useful, especially if you have risk factors such as:

• A family history of diabetes

• Being overweight

• High blood pressure or high cholesterol

• Sedentary lifestyle

• A diet high in processed foods or sugar

Many people with prediabetes don’t realise their glucose is creeping up until it’s picked up by a blood test. Identifying this early means you can make changes to reduce your risk of developing type 2 diabetes.

What happens if your blood glucose is too high or too low?

• High blood glucose (hyperglycaemia): May be caused by diabetes, stress, illness or certain medications. Long-term, it increases the risk of heart disease, kidney problems and nerve damage.

• Low blood glucose (hypoglycaemia): Less common in people without diabetes, but can occur if you haven’t eaten for a long time, exercised intensely or consumed too much alcohol. Symptoms can include shakiness, sweating, dizziness and confusion.

If results are outside the normal range, your healthcare provider may suggest further tests, lifestyle changes or treatment depending on the cause.

How often should you check your blood glucose?

• For people with diabetes: frequency depends on treatment - it may range from several times a day (if using insulin) to periodic checks.

• For those without diabetes but with risk factors: an annual or bi-annual test may be recommended.

• For routine health monitoring: a blood glucose check can be included as part of a wider health assessment.

Your GP or healthcare provider can advise on the best schedule for your circumstances.

Make informed choices with blood glucose testing

Checking your blood glucose is a simple but powerful way to understand more about your health. Whether through a finger-prick test, continuous monitoring or a private blood test, it can provide early warning signs of problems and help you make positive lifestyle choices.

At Bluecrest Wellness, our comprehensive Health MOTs include blood glucose checks and HbA1c testing, which provides insight into your average blood sugar levels over the previous three months. You’ll receive clear, easy-to-understand results, plus 12 months’ access to a 24/7 GP helpline for advice and support.

With convenient clinics across the UK and fast, reliable results from trusted UK laboratories, we make it easy to take control of your wellbeing.

BOOK A PRIVATE HEALTH MOT TODAY

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0800 652 2183 to speak to one of our team.