Blood tests for acromegaly
Tests may be done to help measure the levels of growth hormone and insulin-like growth factor 1 (IGF-1) in your blood. These tests can be carried out without you having to stay overnight in the hospital, although if you live far from the hospital you may need to arrange to stay somewhere overnight.
The diagnosis of acromegaly requires higher than normal levels of both growth hormone and IGF-1 to be recorded.
Oral glucose tolerance test
For the oral glucose tolerance test, or OGTT, you won’t be able to eat or drink anything for about 8 hours before the test.
When you arrive at your doctor’s office or the lab, a healthcare professional will take a sample of your blood. You will then be given a glucose (“sugary”) drink.
After 2 hours, a healthcare professional will take another sample of your blood. After this, you will be able to have something to eat and go home.
If you have acromegaly, your growth hormone levels will remain high throughout the test. This will happen even after a glucose drink, which would normally result in the growth hormone levels decreasing to very low levels.
The three main elements of the oral glucose tolerance test
Some of the blood you provide for the growth hormone test will be sent to a laboratory to measure your levels of IGF-1.
IGF-1 is a naturally occurring hormone produced by the liver that mediates nearly all of the actions of growth hormone on the tissues of the body.
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