Introduction
At any time of life, it is possible for a person to develop the condition known as “diabetes mellitus”. This occurs when the pancreas cannot produce enough of the hormone insulin, which helps to control the amount of sugar in the blood. As a result, blood sugar levels can rise to abnormally high levels. This needs to be recognised and treated to prevent the development of further complications. Your doctor thinks that you may have developed diabetes mellitus. The glucose tolerance test will help to determine whether this is so.
The glucose tolerance test involves drinking a large amount of sugar, usually in the form of a sugary drink. We measure blood sugar levels before the drink and then again two hours afterward to check that your blood sugar is normal and that the sugar in the drink is being metabolised properly.
During Your Test
Before the test begins, the Phlebotomist will take a
finger prick sample and use a glucose meter to measure your blood sugar quickly. If the level is very
high or very low, the Phlebotomist will take a venous
blood sample to be analysed in the laboratory to confirm the high result - if your blood sugar is too high
or low the glucose tolerance test will not proceed, as
it could cause your blood sugar levels to become
dangerously abnormal.
If the finger prick glucose result is normal or only
slightly high or low, the glucose tolerance test will
proceed.
The Phlebotomist will first take a blood sample from
a vein in your arm, then you will be asked to drink a
sugary drink. You will then need to wait in the Outpatients department for two hours, without smoking,
eating or drinking (other than water).
If you feel unwell at any time, please inform a
member of staff immediately.
After two hours, the Phlebotomist will take a second
blood sample from a vein in your arm.
The test is then complete, and you will be able to
leave the hospital. The test should not have any lasting effects, and you will be able to eat and drink normally, and to drive home.
After Your Test
The results of your glucose tolerance test will be
available the following day, and will be sent directly
to your GP (or the doctor or nurse who requested the
test).
The laboratory is not able to give results directly to
patients. You should contact your GP surgery to arrange an appointment to discuss the results.
Our Laboratories
Blood Sciences Department
Surrey Pathology Services
Frimley Park Hospital
Portsmouth Road, Frimley
GU16 7UJ
Royal Berkshire Hospital
Craven Road, Reading
RG1 5AN
Royal Surrey County Hospital
Egerton Road, Guildford
GU2 7XX
St Peters Hospital
Guildford Road, Chertsey
KT16 0PZ
Wexham Park Hospital
Wexham, Slough
SL2 4HL
Useful Contact Numbers
If you would like to learn more about this test, or any
other test that your doctor has ordered, you can visit LabTestsOnLine which is a free resource created and
updated by laboratory professionals for patients:
http://www.labtestsonline.org.uk/
For enquiries please contact our Help Line:
Surrey: 01276 604595
Berkshire: 0800 0327 105
Biochemistry- Patient information for glucose tolerance test
