A test that can be performed to help diagnose hyperthyroidism is:

A test that can be performed to help diagnose hyperthyroidism is:

• A. Cortisol
• B. Bile acids
• C. LH
• D. T4

Answer: (D)

Measuring thyroid hormone levels is how hyperthyroidism is diagnosed. Thyroxine (T4) is a primary circulating thyroid hormone, and when the thyroid is overactive, T4 levels rise. Checking T4 directly helps confirm excess thyroid activity. In practice, clinicians also look at TSH and free T4 for a clearer picture, but among the given options, T4 best serves to indicate hyperthyroidism. The other substances—cortisol, bile acids, and LH—reflect functions of the adrenal glands, liver/digestion, and reproductive system, respectively, and do not assess thyroid function.

Measuring thyroid hormone levels is how hyperthyroidism is diagnosed. Thyroxine (T4) is a primary circulating thyroid hormone, and when the thyroid is overactive, T4 levels rise. Checking T4 directly helps confirm excess thyroid activity. In practice, clinicians also look at TSH and free T4 for a clearer picture, but among the given options, T4 best serves to indicate hyperthyroidism. The other substances—cortisol, bile acids, and LH—reflect functions of the adrenal glands, liver/digestion, and reproductive system, respectively, and do not assess thyroid function.