diabetes specialist tests overview

Overview

Diabetes is a condition where your blood sugar (glucose) level is too high. Glucose comes from the food you eat and is the main source of energy for your body. Insulin, a hormone made by the pancreas, helps glucose get into your cells. In diabetes, either your body doesn’t make enough insulin or it can’t use it properly. Specialist tests help diagnose diabetes and monitor how well it is being managed.

Yes, diabetes is very common. According to the NHS, over 4 million people in the UK have diabetes, and many more may have it without knowing.

Diabetes can affect people of all ages, including children, adults, and older adults. Type 1 diabetes often starts in childhood or young adulthood. Type 2 diabetes is more common in adults over 40, but it is increasingly seen in younger people due to lifestyle factors. Gestational diabetes occurs during pregnancy.

Symptoms

Common symptoms

• Feeling very thirsty often
• Urinating (peeing) more than usual, especially at night
• Feeling very tired
• Unexplained weight loss
• Blurred vision
• Slow-healing cuts or sores
• Tingling or numbness in hands or feet

Symptoms in children

• Frequent urination – a child who has been dry may start wetting the bed at night
• Extreme thirst
• Weight loss despite eating more
• Fatigue and irritability
• Fruity-smelling breath (a sign of high ketones)

Symptoms in older adults

• Increased thirst and urination
• Blurred vision
• Fatigue
• Slow-healing infections
• Confusion or dizziness (if blood sugar is very high or low)

Causes

Main causes

• Type 1 diabetes: The immune system attacks and destroys the insulin-producing cells in the pancreas. The exact cause is unknown, but it may involve genetics and a trigger like a virus.
• Type 2 diabetes: The body becomes resistant to insulin or the pancreas does not make enough insulin. This is often linked to lifestyle factors such as being overweight, not being physically active, and poor diet.
• Gestational diabetes: Hormonal changes during pregnancy can cause insulin resistance. It usually goes away after the baby is born but increases the risk of type 2 diabetes later.

Risk factors

• Family history of diabetes
• Being overweight or obese
• Being over 40 (or 25 for South Asian people)
• Low physical activity
• Unhealthy diet high in sugar and fat
• High blood pressure or high cholesterol
• Previous gestational diabetes or giving birth to a baby weighing over 9 pounds

When to see a doctor

See a doctor urgently if:

• If you have symptoms of very high or very low blood sugar (see emergency symptoms above)
• If you have been diagnosed with diabetes and have vomiting or severe illness

Book a routine appointment if:

• If you have persistent symptoms like thirst, frequent urination, or unexplained weight loss
• If you have risk factors and are over 40 (or 25 if South Asian)
• If you are pregnant and offered screening for gestational diabetes

Diagnosis

Diabetes is diagnosed using blood tests that measure your blood sugar levels. Specialists (endocrinologists) or your GP can order these tests. The results show whether your blood sugar is above the normal range.

Tests that may be done

• HbA1c test – shows your average blood sugar over the past 2 to 3 months. A result of 48 mmol/mol or higher (6.5% or higher) indicates diabetes.
• Fasting plasma glucose test – measures blood sugar after you have not eaten for at least 8 hours. A level of 7.0 mmol/L or higher suggests diabetes.
• Oral glucose tolerance test (OGTT) – you drink a sugary liquid, and blood sugar is measured before and after. A result of 11.1 mmol/L or higher after 2 hours indicates diabetes.
• Random plasma glucose test – a blood sugar level of 11.1 mmol/L or higher with symptoms can also diagnose diabetes.
• Urine test – may be done first to check for sugar in urine, but a blood test is needed for confirmation.

What to expect at your appointment

Your doctor will explain which test is right for you. For the HbA1c test, you don’t need to fast. For fasting glucose or OGTT, you’ll need to avoid food and drink (except water) for 8 hours. The tests involve a simple blood draw, and results come back within a few days. You will then discuss the results with your healthcare provider.

Treatment

Treatment for diabetes aims to keep your blood sugar levels as close to normal as possible and prevent complications. It depends on the type of diabetes, your age, and your overall health. Always follow the plan your healthcare team gives you.

Self-care at home

• Check your blood sugar regularly as advised by your healthcare team
• Take all prescribed medicines exactly as directed
• Eat a healthy, balanced diet – focus on vegetables, whole grains, and lean proteins
• Stay active – aim for at least 150 minutes of moderate exercise each week
• Manage stress – try deep breathing, mindfulness, or talking to someone
• Check your feet daily for cuts, blisters, or sores

Medical treatments

Medical treatments for diabetes include lifestyle advice, oral medications (tablets) to lower blood sugar, and/or injectable medications such as insulin or non-insulin injectables. The type of medicine depends on the type of diabetes and individual needs. For type 1, lifelong insulin is essential. For type 2, often a combination of lifestyle changes and medicines is used. Your doctor will work with you to find the best plan. Never adjust medication without speaking to your healthcare team.

When is surgery considered?

Surgery is not a common treatment for diabetes itself. However, bariatric (weight loss) surgery may be considered for some people with type 2 diabetes who have a very high body mass index (BMI) and have not achieved control with other treatments. This is only after a thorough assessment by a specialist team.

Living with this condition

Living with diabetes means checking your blood sugar, taking medications, eating carefully, and staying active. It can feel like a lot, but many people manage it well with support. Your healthcare team will help you learn the skills you need. Over time, these habits become part of your routine.

Lifestyle tips

• Eat regular meals and snacks to keep blood sugar steady
• Choose water or sugar-free drinks
• Limit sugary foods, sweets, and white bread or pasta
• Stay physically active every day – even walking helps
• Get enough sleep – aim for 7-9 hours a night
• Avoid smoking and limit alcohol

Diet and exercise

A diabetes-friendly diet includes plenty of vegetables, fruits (in moderation), whole grains, lean meats, fish, and healthy fats like olive oil. Avoid sugary snacks and drinks. Exercise helps lower blood sugar – try brisk walking, swimming, cycling, or dancing. Always check with your doctor before starting a new exercise program, especially if you have other health issues.

Mental health and emotional wellbeing

Living with diabetes can be stressful and sometimes overwhelming. It is common to feel anxious, frustrated, or burnt out. You may feel worried about complications or managing daily tasks. If you are struggling with your emotions, talk to your healthcare team. They can offer support or refer you to a mental health professional. If you have thoughts of harming yourself, contact a crisis helpline or call your local emergency number.

Prevention

Type 1 diabetes cannot be prevented at this time. However, type 2 diabetes can often be prevented or delayed by maintaining a healthy weight, eating well, and being physically active. For people at high risk (prediabetes), lifestyle changes are especially effective. Gestational diabetes usually goes away after birth, but the risk of developing type 2 later is higher, so prevention after pregnancy is important.

Vaccines

People with diabetes are advised to get the annual flu vaccine, the pneumococcal vaccine, and the COVID-19 vaccine as recommended by health authorities. These help prevent infections that can make diabetes harder to control.

Screening programmes

The NHS offers screening for type 2 diabetes for people at high risk, such as those over 40 (or 25 if South Asian), those with a family history, or those who are overweight. Pregnant women are offered screening for gestational diabetes between 24 and 28 weeks.

Complications

If left untreated

• Heart disease and stroke – high blood sugar damages blood vessels
• Kidney disease (nephropathy) which can lead to kidney failure
• Eye damage (retinopathy) that can cause vision loss or blindness
• Nerve damage (neuropathy) causing pain, tingling, or loss of feeling, especially in feet
• Foot problems such as ulcers, infections, and in severe cases, amputation
• Skin infections and slow healing
• Increased risk of infections like gum disease

Long-term outlook

With good management, many people with diabetes live long, healthy lives. Keeping blood sugar in target range, controlling blood pressure and cholesterol, and not smoking greatly reduce the risk of complications. Regular check-ups with your healthcare team help catch any problems early when they are easier to treat. A diabetes diagnosis is not a sentence – it is a condition that can be managed with the right support and care.

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