Prolactin

Serum Prolactin PRL

Serum (SST; 1–2h after waking, avoid stress) mIU/L

About this test

Pituitary hormone primarily regulating lactation. Hyperprolactinaemia suppresses GnRH, causing hypogonadism and infertility. Stress, exercise, and certain drugs cause physiological elevation.

Reference Ranges

Sex	Age	Range	Notes
Female	≥ 18 yrs	102 – 496	Adult female (non-pregnant); much higher in pregnancy/lactation
Male	≥ 18 yrs	86 – 324	Adult male

Clinical Interpretation

Low / Decreased

Low — panhypopituitarism.

High / Increased

Elevated — prolactinoma (most common pituitary tumour), hypothyroidism (TRH stimulates prolactin), drugs (antipsychotics, metoclopramide, opioids), stress, pregnancy, chest wall stimulation, renal failure, stalk compression.

Specimen

Serum (SST; 1–2h after waking, avoid stress)

Reporting Unit

mIU/L