“I had blood tests and my insulin-like growth factor level was very high”
This patient testimonial reflects only this person’s opinions about their own care. Each person’s case is unique and you should always consult a doctor for information and advice about the diagnosis and treatment of acromegaly.
Please note that the tests used to diagnose acromegaly may vary according to your particular situation and to local healthcare practices.
The oral glucose tolerance test, or OGTT, usually involves fasting from about 10 pm the evening before an early morning appointment at the hospital.
Blood samples are then taken every half an hour from a catheter (thin plastic tube) that is placed in a vein in your arm.
After the first blood sample you will be given a glucose (‘sugary’) drink.
Further blood samples will be taken every 30 minutes over a period of about 2–3 hours. After this, you will be able to have some breakfast 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.
Looking at how levels of your growth hormone change throughout the day is a test that some hospitals may use to monitor the effectiveness of treatment for acromegaly.
This test also involves fasting from about 10 pm the evening before an early morning appointment at the hospital.
To perform this test, a needle is placed in your arm and blood will be taken at intervals over several hours.
After the first sample is taken, you can have breakfast and you will be able to move about freely.
The results of the tests will usually be available in about 1 week, but this may vary from one hospital to another and may take up to 2–3 weeks.
Learn about acromegaly including what causes this slowly evolving condition, and the early signs and symptomsLearn about acromegaly
Read about acromegaly treatment options, including surgery, medications and radiotherapy, and the goals of therapyTreating acromegaly
Read and hear answers to some common questions that patients with acromegaly have askedView FAQs