What does GTT stand for and what type of tube would you collect?

GTT stands for Glucose Tolerance Test. Blood tubes required:

* Green top - Serum for Glucose and Insulin (F)

* Pink top - EDTA for Glycated haemoglobin A1c and fructosamine

The test measures how the body responds to the intake of glucose over 2 and a half hours, assessing for impaired glucose tolerance and diabetes.

- A blood sample will be taken after at least an 8-hour fast (usually in the morning). This is your 0-hour test

- You will then drink a glucose solution

- More blood tests will be taken and 1 and 2-hours for a glucose reading then again after 2 hrs for the remaining measurements