Tests for Diagnosing
and Monitoring Acromegaly

When acromegaly is suspected, securing biochemical evidence is imperative. Diagnostic tools used to determine a diagnosis include the following:

  • Blood test to measure serum insulin-like growth factor-1 (IGF-1)—Acromegaly in the absence of elevated IGF-1 levels is rare; this test is ideal for diagnosis. It's also considered useful for measuring IGF-1 levels following treatment, such as surgery.1,2
  • Oral glucose tolerance test (OGTT)—For almost 40 years the measurement of growth hormone (GH) during an oral glucose test has been standard. Following ingestion of a glucose drink, GH levels in normal patients should fall below 1 ng/mL. In patients with acromegaly, oral glucose does not suppress GH.1,2
  • Random GH testing—While GH levels are usually elevated in the presence of acromegaly, serum concentrations can fluctuate, so a 24-hour sample is necessary to make this test useful.3
  • Imaging—Following a diagnosis of acromegaly by measuring GH or IGF-1 levels, a magnetic resonance imaging (MRI) scan of the pituitary may be used to locate and detect the size of the tumor causing GH overproduction. If a patient cannot have an MRI, computed tomography (CT) scans can be used as well, although an MRI is considered a more sensitive technique.1,2
References:
Katznelson L, Laws ER Jr, Melmed S, et al. Acromegaly: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2014;99(11):3933-3951.
National Institute of Diabetes and Digestive and Kidney Diseases. Acromegaly. https://www.niddk.nih.gov/health-information/endocrine-diseases/acromegaly#treatment. Accessed April 27, 2017.
Lugo G, Pena L, Cordido F. Clinical manifestations and diagnosis of acromegaly. Int J Endocrinol. 2012;2012:540398.
Collaborative Team Management: Your Role Acromegaly is usually managed by an endocrinologist, but the first signs of the disease may be identified by other specialties. Discover how general practitioners, dentists, cardiologists, rheumatologists, and other experts can work together to help diagnose and manage acromegaly.
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