The most reliable test for acromegaly is the __________.

The most reliable test for acromegaly is the __________.

• A. thyroid-stimulating hormone level
• B. glucose tolerance test
• C. parathyroid hormone
• D. cortisol level

Answer: (B)

Acromegaly is caused by excessive growth hormone (GH) secretion from a pituitary adenoma, and a key diagnostic feature is how GH responds to a glucose challenge. Normally, when a glucose load is given, GH secretion is suppressed to very low levels. In acromegaly, the GH secretion is autonomous and does not suppress with glucose; the GH level remains elevated after the glucose challenge (and may even rise). This failure to suppress during an oral glucose tolerance test provides clear, functional evidence of GH excess, making it the most reliable diagnostic test for acromegaly. IGF-1 is a helpful screening marker because it reflects average GH activity, but the OGTT with GH suppression is the definitive test. The other measures listed (TSH, PTH, cortisol) assess different endocrine systems and do not evaluate GH dynamics.

Acromegaly is caused by excessive growth hormone (GH) secretion from a pituitary adenoma, and a key diagnostic feature is how GH responds to a glucose challenge. Normally, when a glucose load is given, GH secretion is suppressed to very low levels. In acromegaly, the GH secretion is autonomous and does not suppress with glucose; the GH level remains elevated after the glucose challenge (and may even rise). This failure to suppress during an oral glucose tolerance test provides clear, functional evidence of GH excess, making it the most reliable diagnostic test for acromegaly.

IGF-1 is a helpful screening marker because it reflects average GH activity, but the OGTT with GH suppression is the definitive test. The other measures listed (TSH, PTH, cortisol) assess different endocrine systems and do not evaluate GH dynamics.