Hi, yeah, I've had several for the purposes of diagnosis and for elimination of other conditions such as insulinoma, pancreatitis and pancreatic cancer.
This method of testing is called an extended oral glucose tolerance test, eOGTT for short.
It's at least a twelve hours fast before taking readings and samples before 175g(?) Of glucose.
A cannula is fitted, of which a sample is taken every half hour as well as finger prick testing every fifteen minutes in my case. This test can last up to six hours but will be stopped if the patient goes hypo. (Under 3.7 mmols)
The purpose of each eOGTT is to track what happens to your glucose levels on a standard test to seek abnormal spikes and drops. And to see your levels at two hours.
If you are relatively normal your blood glucose levels should be about or within two mmols above from your fasting levels.
It also tracks your insulin response and how weak or strong your first insulin response is and the timing of your secondary response.
You will have a c-peptide, GAD test, and you should get your insulin levels tested to see how high your circulating insulin levels are.
Hyperinsulinaemia is a common reason for prediabetes and then T2.
In a two hours glucose test, the glucose levels difference is higher than the 2mmols because of the insulin resistance. Also the lack of insulin in those who are not creating enough insulin.
Hope that helps.
