Glucose – Tolerance test
Alternative Names: GTT
A Glucose Tolerance Test (GTT) measures how the body responds when a measured amount of glucose (sugar) has been eaten. The test is used to diagnose or exclude diabetes. You have nothing to drink or eat for 12 hours before the test. Blood is withdrawn through a needle from a vein, usually on the inside of the elbow, to measure your blood glucose level. Then you are given some glucose, and further blood samples are taken over 2-3 hours. It is important to control blood sugar levels so as to reduce the risk of long-term complications from diabetes such as angina and heart attack (ischaemic heart disease), stroke, kidney disease, eye problems, and poor circulation.
What is it?
A Glucose Tolerance Test, or GTT, measures how the body responds to the ingestion of a measured amount of glucose (sugar).
The test can be drawn at your doctor’s rooms, a clinic, or in hospital. The analysis of the specimens is done in a laboratory.
Why is it done?
This test is sometimes used when trying to diagnose or exclude diabetes.
What happens?
Before – how to prepare
You need to fast – eat and drink nothing, except water – for 12 hours before the test.
During – how the test is done
First a blood specimen is taken to measure you fasting blood glucose level. You are then given a measured amount of glucose (sugar) – usually 75g. Blood specimens are taken every 30 minutes for 2-3 hours. Doctors can then determine just how your body metabolises a known amount of sugar, which allows them to decide if you have diabetes or not.
The blood is taken thus: A convenient area, where there are prominent veins, is identified and cleaned – the area inside the elbow is often used. A tourniquet or tight band is applied above the area in order to increase pressure and dilate the veins. A needle is then inserted, through the skin, into a vein, and some blood is withdrawn. The needle may cause some pain, but this is not usually severe.
After the test
You will have a small dressing over the puncture wound, which can be removed after a few hours..
Risks and Compilations
There is a slight risk of excessive bleeding at the puncture site and an even smaller risk of infection.
Special Issues
This test is performed less often these days, because the fasting blood glucose test is often considered sufficient to diagnose or exclude diabetes.
It well known that good blood sugar control reduces the risk of long-term diabetic complications such as ischaemic heart disease (angina and heart attack), stroke, kidney disease, eye problems, and poor circulation. If you have diabetes it is very important to make very effort to achieve good sugar control.
Short Description
A Glucose Tolerance Test (GTT) measures how the body responds when a measured amount of glucose (sugar) has been eaten.
Keywords
glucose tolerance test, GTT