Library · Test
Glucose tolerance test
Make it clearer
The glucose tolerance test is a lab test that measures one very specific thing: whether your body uses and stores glucose, the sugar in your blood, normally. It is used to evaluate diabetes mellitus and insulin resistance, which is when tissues respond poorly to that hormone.
In the most common version, the oral one, you are given a fixed amount of glucose to drink and your blood glucose is measured two hours later. It is like filling a tank all at once and coming back two hours later to see how much is still inside: what is measured is not the drink, but how the blood looks after that stretch of time.
That is why the prep is part of the test and not a formality. It calls for a fast of ten to sixteen hours, and for the person to have eaten without restrictions in the days before.
A single result does not close the matter either: to confirm a diagnosis, the test has to be repeated on another day and give a similar result.
In brief
The glucose tolerance test measures whether the body uses and stores glucose normally. It is used to evaluate diabetes mellitus and insulin resistance.
In the most widely used version, the oral one, you drink a standard dose of glucose and blood glucose is measured two hours later.
The prep is part of the test: ten to sixteen hours of fasting and an unrestricted diet in the days before.
Confirming a diagnosis requires repeating the test on another day with a similar result.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingGlucose Tolerance Test, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated