Diagnosing and Monitoring Acromegaly
Several tests are useful in diagnosing and monitoring acromegaly. The most important are laboratory tests that measure the levels of GH and IGF-1 in the blood. Because these levels vary naturally depending on factors such as your age, the time of day, and when you last ate, there are 2 main approaches to measuring your GH and IGF-1 levels.
Multiple tests
. 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.
| Normal GH Levels | Normal IGF-1 Levels |
|---|---|
Normal GH levels vary, depending on when the measurement is taken:
|
Normal IGF-1 levels depend on your age and gender, and the reference numbers may vary slightly depending on which laboratory provides the results. |
| Levels of GH and IGF-1 are often measured in ng/mL, which stands for nanograms per milliliter. Please note that the reference numbers can be slightly different depending on the assays used for testing and on the laboratory your health care professional uses, but all are accurate methods of monitoring the progress of your treatment. Of course, treatments may not always result in a complete reduction of GH or IGF-1 to within these "normal" ranges. Please talk to your health care professional about your test results and what they mean for you. | |
Other tests, such as head scans by magnetic resonance imaging (MRI) or computed tomography (CT), are designed to look for a pituitary growth or tumor, the most likely source of the excessive GH secretion. Normally, these tests are performed on an outpatient basis inside a hospital or clinic and involve no special preparation on your part. Head scans are a way to provide your health care provider with "photographs" of the inside of your head.
Still other tests, such as an electrocardiogram (ECG), chest X-ray, eye and visual field examination, and/or colonoscopy, will help your doctor check your overall health. These tests also usually do not require hospitalization and are performed by health care specialists in different fields. These specialists and/or technicians will send all test results directly to your health care provider. Your health care professional will then provide you with your test results, as well as specific information regarding your current levels of GH and IGF-1. You may want to understand the results of all of your tests and learn your GH and IGF-1 levels so that you can become an active participant in your own treatment.
