In suspected acromegaly, which test is used for screening?

In suspected acromegaly, which test is used for screening?

• A. IGF-1 level
• B. Prolactin level
• C. 24-hour urinary free cortisol
• D. TSH

Answer: (A)

IGF-1 level is the screening test for suspected acromegaly because Growth Hormone (GH) levels fluctuate with pulses and throughout the day, making a single GH measurement unreliable. IGF-1, produced by the liver in response to GH, stays relatively stable and reflects overall GH exposure, so it’s a more accurate initial screen. If IGF-1 is elevated, it points toward excess GH production and leads to confirmatory testing, typically an oral glucose tolerance test to see if GH suppresses appropriately. Prolactin, 24-hour urinary free cortisol, and TSH assess other pituitary or endocrine issues and are not appropriate screening tests for GH excess.

IGF-1 level is the screening test for suspected acromegaly because Growth Hormone (GH) levels fluctuate with pulses and throughout the day, making a single GH measurement unreliable. IGF-1, produced by the liver in response to GH, stays relatively stable and reflects overall GH exposure, so it’s a more accurate initial screen. If IGF-1 is elevated, it points toward excess GH production and leads to confirmatory testing, typically an oral glucose tolerance test to see if GH suppresses appropriately. Prolactin, 24-hour urinary free cortisol, and TSH assess other pituitary or endocrine issues and are not appropriate screening tests for GH excess.