Making a diagnosis

Discovering that you have diabetes

People find out they have the condition in different ways. With type 2, the first port of call is usually your GP, either because you have some or all of the symptoms listed on page 7, or because you are having a general check-up.

Some people are advised to see their doctor by their optician (or optometrist). This is because an eye examination will pick up the early signs of a condition called diabetic retinopathy – changes in the blood vessels of the eye that can develop as a complication of diabetes (see page 110).

Tests for diabetes

If your symptoms suggest to your doctor that you may have diabetes, he or she will want to do a blood test to measure your glucose level, and will also ask for a urine sample to be tested. The samples may have to be sent off to the lab for analysis, although most GPs today have blood glucose meters in the surgery, and can give you the result on the spot. Some pharmacies are also offering blood tests for people who are worried that they may have diabetes.

The structure of diabetes care

Above-average readings from either or both of these tests will probably be sufficient for your doctor to confirm that you have diabetes and, if it’s type 2, it’s likely that you will be cared for by your GP rather than having to see a hospital doctor.

Many GP practices run regular diabetes clinics but, if yours doesn’t or you feel that you need more support, you can ask to be referred to a hospital diabetes clinic.

As mentioned above, type 1 diabetes can often come on quite suddenly, and this may mean the person being admitted to hospital while the diagnosis is made and the condition stabilised.
People with this form of diabetes will often continue to be under the care of the specialist team at a hospital. Nowadays, many patients with type 1 and type 2 diabetes have shared care between the hospital and the GP.

Although, for most people, the diagnosis is straightforward and quite clear cut, a few may need an extra test because their blood glucose level is borderline. In this case, you may be asked to have an oral glucose tolerance test. After an overnight fast, your blood glucose level will be measured on arrival at the clinic; then you’ll be given a drink containing a measured amount of glucose. Your blood will be re-tested at two hours to see how your body is dealing with the glucose that you’ve absorbed. You may also be asked to pass a urine sample at the start and end.

Oral glucose tolerance test

If your blood tests show that your blood glucose level is borderline you may need an oral glucose tolerance test. There are three possible outcomes, depending on the results of your test:

1. Your blood glucose may be within the normal range, so you don’t have diabetes.
2. Your level may be higher than average, although not high enough to mean that you have diabetes. This condition is called impaired glucose tolerance (IGT) and your medical advisers will want to keep an eye on you because there is a possibility of developing diabetes in the future. In the meantime you will be given advice on diet, although you don’t have diabetes and don’t need any other specific treatment.
3. Your blood glucose level may be sufficiently raised to indicate that you do have diabetes. If so, you will need to see your doctor to discuss what treatment you need.

KEY POINTS

• Diabetes is usually diagnosed from a simple urine or blood test in patients who have symptoms

• A small number of patients need to have a more formal test called an oral glucose tolerance test

• Early diagnosis is very important and patients with symptoms are recommended to attend their GP’s surgery or local pharmacy for a test