How is acromegaly diagnosed?Diagnosis of acromegaly begins with a medical history and physical exam. It may take years after the first symptoms appear to diagnose acromegaly. This is because the changes occur so slowly. A blood test to measure the levels of human growth
hormones, called HGH, is helpful in diagnosis. Many people with acromegaly develop high blood glucose levels, so this sign may prompt a doctor to investigate further.
A blood test can measure the level of growth hormone. But, a single test is not reliable. The diagnosis of acromegaly is made by a glucose tolerance test. In this test you drink a sugar drink containing 75 gram glucose. You then have a series of blood tests over two hours. The glucose should lower the blood level of growth hormone, but in acromegaly the growth hormone level remains high. A blood test to measure the level of IGF-I (see above) may be measured if acromegaly is suspected. This may also be used as an index of disease activity to assess how well treatment is working. An MRI scan (magnetic resonance imaging scan) or CT scan (computed tomography scan) can show the size of the tumour. Eye and visual tests will assess if the tumour is pressing on the optic nerve. If you are confirmed as having acromegaly, other tests will be needed to see if the tumour is causing a lack other hormones made by the pituitary.