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Diagnosing Acromegaly

To diagnose acromegaly, your doctor will take blood samples and test them for increased IGF-1 and GH levels. Upon diagnosis, the first treatment route for most patients is surgery to remove the pituitary tumor. If hormone levels do not return to normal, the doctor may prescribe therapy with medicine. Even when surgery is successful and hormone levels return to normal, people with acromegaly must be carefully monitored for years for possible recurrence of the disease.

Tests for Diagnosing and Monitoring Acromegaly

Several tests are useful in diagnosing and monitoring acromegaly. The most important are laboratory tests that measure the levels of growth hormone (GH) in the blood. Because these levels vary naturally depending on factors (age, the time of day, and when you last ate) there are 2 main approaches to measuring your GH.

  • Random GH testing: To compensate for the variation in levels, your doctor may average the values from a series of "random" blood tests.
  • Oral glucose tolerance test (OGTT): Alternatively, a way to get an accurate reading in a single measurement is to take the blood sample after you do an overnight fast, followed by an early morning drink of concentrated glucose solution.

Additionally, insulin-like growth factor-1 (IGF-1) levels can be measured, as acromegaly in the absence of elevated IGF-1 levels is rare. These levels vary by age and gender and need to be adjusted accordingly. The test for IGF-1 levels is a blood test.

  • Blood test for IGF-1 levels: Because IGF-1 is released more evenly than GH, and these levels remain higher longer, IGF-1 levels can be taken at any time, with a blood test.

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