Prolactin, Serum (Mass Concentration)

Why This Test Might Be Ordered

Your doctor may recommend this test if you have symptoms like unusual breast milk production (galactorrhea), irregular menstrual periods, infertility, headaches, or signs of a pituitary tumor. It could also be checked during evaluations for thyroid disorders, certain cancers, or unexplained symptoms like fatigue or weight changes.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to avoid certain medications (like some antidepressants or antipsychotics) that can affect prolactin levels. If you’re breastfeeding, let your doctor know—this test may not be appropriate during that time.

What the Test Involves

A blood sample will be drawn from a vein, typically in your arm. The sample is sent to a lab for measurement using an immunoassay method to detect prolactin in your serum.

What the Results Mean

Results are compared to a general reference range, but individual ranges can vary by lab. High prolactin levels may indicate conditions like pituitary tumors, thyroid issues, or medications affecting hormone balance. Low levels might suggest rare pituitary disorders or other hormonal imbalances.