From the Guidelines
For a patient presenting with galactorrhea, initial laboratory testing should include a prolactin level, as hyperprolactinemia is the most common cause of galactorrhea, and assessing baseline macroprolactin levels is recommended where serum prolactin is found to be mildly or incidentally elevated 1.
Initial Laboratory Tests
The following tests are essential for the initial evaluation:
- Prolactin level: to assess for hyperprolactinemia, which is the most common cause of galactorrhea
- Pregnancy test (in women of reproductive age): as pregnancy naturally elevates prolactin levels
- Thyroid-stimulating hormone (TSH): to identify hypothyroidism, which can cause secondary hyperprolactinemia
- Comprehensive metabolic panel and renal function tests: to evaluate for conditions like liver or kidney disease that can affect prolactin metabolism
Additional Testing
If prolactin is elevated, additional testing may include:
- Magnetic resonance imaging (MRI) of the pituitary to rule out prolactinoma or other sellar masses
- In cases with normal prolactin but persistent symptoms, consider medication review as drugs like antipsychotics, antidepressants, and antihypertensives can cause galactorrhea without elevating prolactin
- For women, estrogen and progesterone levels may be checked to assess ovarian function, while men might need testosterone measurement
According to the consensus guideline for the diagnosis and management of pituitary adenomas in childhood and adolescence, serum prolactin measurement is recommended in children and young people (CYP) presenting with galactorrhoea, among other signs and symptoms 1. Additionally, the evaluation of women with epilepsy for reproductive endocrine disorders may involve hormonal measurements, pelvic ultrasonography, and pituitary imaging, including tests for prolactin levels and pituitary magnetic resonance imaging if indicated by clinical features or laboratory results 1. However, the most recent and highest quality study 1 prioritizes the assessment of baseline macroprolactin levels in the initial investigation of asymptomatic individuals with hyperprolactinaemia.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Laboratory Tests for Galactorrhea
To evaluate a patient presenting with galactorrhea, several laboratory tests should be ordered, including:
- Prolactin level measurement to assess for hyperprolactinemia, a common cause of galactorrhea 2, 3
- Pregnancy test to rule out pregnancy as a cause of galactorrhea, especially in premenopausal women 2, 3
- Thyroid-stimulating hormone (TSH) level assessment to evaluate for hypothyroidism, which can cause hyperprolactinemia and galactorrhea 2, 3, 4
- Renal function tests to assess for renal insufficiency, which can also cause hyperprolactinemia and galactorrhea 2, 3
Additional Tests
Depending on the results of the initial laboratory tests, additional tests may be ordered, including:
- Brain magnetic resonance imaging (MRI) to evaluate for pituitary adenomas or other sellar or suprasellar lesions if no other cause of hyperprolactinemia is found 2, 3
- Pituitary MRI to identify pituitary tumors in patients with persistently elevated prolactin levels 5
Rationale
These laboratory tests are necessary to determine the underlying cause of galactorrhea and to guide treatment. Hyperprolactinemia is a common cause of galactorrhea, and measuring prolactin levels can help diagnose this condition. Ruling out pregnancy and assessing thyroid and renal function can also help identify other potential causes of galactorrhea. If a pituitary adenoma or other lesion is suspected, brain MRI or pituitary MRI may be necessary to confirm the diagnosis.