What laboratory test can help diagnose acromegaly?

The insulin-like growth factor 1 (IGF-1) test is the most relevant laboratory test for diagnosing acromegaly. Acromegaly is a hormonal disorder that results from excess growth hormone (GH), usually caused by a benign tumor on the pituitary gland. GH stimulates the liver and other tissues to produce IGF-1, which mediates many of the growth-promoting effects of GH.

When evaluating for acromegaly, measuring IGF-1 levels provides valuable information because it reflects the chronic effects of growth hormone secretion. Elevated IGF-1 levels in the blood are indicative of excessive growth hormone activity, supporting a diagnosis of acromegaly.

In contrast, while other tests listed may assess different hormonal issues or conditions, they are not diagnostic for acromegaly. For instance, the TSH test evaluates thyroid function and would not directly relate to growth hormone levels. The blood glucose test could be influenced by GH but does not specifically diagnose acromegaly. The cortisol level test is used to assess adrenal function and does not pertain directly to the diagnosis of growth hormone excess. Thus, the IGF-1 test is the most specific and informative marker for diagnosing acromegaly.