The diagnosis of hyperprolactinemia is best evaluated with which tests?

The diagnosis of hyperprolactinemia is best evaluated with which tests?

• A. Serum prolactin levels and TSH
• B. Serum calcium and PTH
• C. CBC and ESR
• D. MRI brain and CT scan

Answer: (A)

The key idea is to confirm elevated prolactin and look for a reversible cause, with hypothyroidism being a classic one that raises prolactin. Start by measuring serum prolactin, preferably from a fasting morning sample, because prolactin can be transiently elevated with stress, exercise, or meals. If prolactin is elevated, the next essential step is to assess thyroid function with TSH, since hypothyroidism increases prolactin via elevated TRH stimulating prolactin release. This combination helps distinguish true hyperprolactinemia and identify a treatable cause. Imaging of the brain, such as MRI, is typically reserved for when hyperprolactinemia is confirmed and persistent, to evaluate for a pituitary adenoma, rather than as an initial assessment. The other options don’t directly address prolactin elevation or its common reversible driver.

The key idea is to confirm elevated prolactin and look for a reversible cause, with hypothyroidism being a classic one that raises prolactin. Start by measuring serum prolactin, preferably from a fasting morning sample, because prolactin can be transiently elevated with stress, exercise, or meals. If prolactin is elevated, the next essential step is to assess thyroid function with TSH, since hypothyroidism increases prolactin via elevated TRH stimulating prolactin release. This combination helps distinguish true hyperprolactinemia and identify a treatable cause. Imaging of the brain, such as MRI, is typically reserved for when hyperprolactinemia is confirmed and persistent, to evaluate for a pituitary adenoma, rather than as an initial assessment. The other options don’t directly address prolactin elevation or its common reversible driver.