A Prolactin test measures the level of prolactin, a hormone produced by the pituitary gland. Prolactin plays an important role in reproductive health, especially in women, as it helps regulate menstrual cycles and supports milk production after childbirth. Elevated prolactin levels (hyperprolactinemia) can cause irregular periods, infertility, unexpected breast milk production, headaches, or vision problems. In men, high prolactin may lead to reduced libido, erectile dysfunction, or low testosterone.

For the Prolactin test, a small blood sample is taken from a vein. Fasting is not always required, but some doctors recommend a morning, fasting sample for more accurate results because prolactin levels can fluctuate throughout the day. This test helps diagnose pituitary gland disorders, hormonal imbalances, and reproductive issues in both men and women.