In the management of a 19-year-old female with secondary amenorrhea, which lab tests are typically prioritized?

In the case of secondary amenorrhea in a 19-year-old female, prioritizing the assessment of thyroid-stimulating hormone (TSH) and prolactin levels is crucial. This is because both thyroid dysfunction and hyperprolactinemia are common causes of secondary amenorrhea.

High prolactin levels can indicate a prolactinoma or other conditions affecting the pituitary gland, which can disrupt normal menstrual function. Similarly, thyroid disorders, particularly hypothyroidism, can lead to menstrual irregularities due to their impact on the hypothalamic-pituitary-gonadal axis. Measuring TSH helps assess thyroid function, while testing for prolactin provides insight into potential hyperprolactinemia.

Determining LH and FSH levels, while also important in evaluating menstrual irregularities, typically comes after initial screening for the more common causes associated with secondary amenorrhea. Consequently, the initial tests should focus on TSH and prolactin to rule out these prevalent conditions first.