Pall Mall Medical logo

Pall Mall Medical - for all your private healthcare needs, whether you are self-paying or have private medical insurance.

Glucose Tolerance Test

Glucose Tolerance Test (GTT)

Book your appointment

A glucose tolerance test is used to test the level at which a person’s body processes glucose (also known as sugar). The results of the test will help endocrinologists (doctors specialising in treating diabetes) to diagnose diabetes, as well as related health issues such as insulin resistance and reactive hypoglycemia.


What happens during an oral glucose tolerance test?

An oral glucose tolerance test (OGTT) is one of the most common glucose tolerance tests and works by confirming whether an individual has difficulty processing sugar, which could indicate diabetes. During the test your blood glucose level will be tested before and after you drink a glucose liquid to measure how quickly your body metabolises the glucose.

On the day of the test, you will be asked not to eat or drink anything after midnight. Once in the clinic, you will have a series of three blood and urine tests - one blood sample and urine sample before the glucose drink, one blood sample and urine sample one hour after and a third blood sample and urine sample an hour later. During the test you will have blood collected 3 times over 2 hours. You will be asked to rest in the waiting room during the test. Smoking, eating and drinking must be avoided.


What do the results from an OGTT show?

The glucose levels of a person who doesn’t suffer from diabetes will rise quickly after drinking the glucose drink and then fall again just as quickly. If a person has diabetes, their glucose levels will rise higher than a person without diabetes and then come back down much more slowly, demonstrating high blood glucose levels in their blood.


Gestational diabetes

Pregnant women are at a higher risk of suffering from diabetes as hormones released during pregnancy can prevent insulin from processing glucose in the blood correctly. If you have been identified as being at a ‘high risk’ of developing diabetes in pregnancy (also known as gestational diabetes), it’s recommended you have an oral glucose tolerance test. Gestational diabetes is not uncommon and is estimated to affect around 14 in every 100 pregnant women.

Risk factors include:

·       A family history of diabetes

·       Being overweight

·       Developing gestational diabetes in a previous pregnancy

·       Having high blood pressure

·       Having an excess of amniotic fluid

·       Having previously given birth to a large baby weighing more than 9.9lb


If any of these risk factors apply to you, or if you are worried about gestational diabetes, speak to one of our experts about having a test to check for gestational diabetes. The test is usually done between 26-28 weeks unless you developed gestational diabetes in a previous pregnancy, in which case you should be tested at 16 weeks.

The test will be performed whilst you relax in the comfort of one of our city centre clinics. Once the test is complete, we will contact you with the results the same day and a printed copy of the result will be available for you to include in your pregnancy notes.


Glucose tolerance test prices



Glucose Tolerance Test (2 samples - 'short')

(excludes appointment, available from £25)


Glucose Tolerance Test (3 samples - 'standard')

(excludes appointment, available from £25)