Lab test
What is a prolactin test, and what are normal prolactin levels?
A prolactin test measures a pituitary hormone whose main job is to make breast milk after birth. It is ordered for irregular periods, infertility, nipple discharge or low sex drive, and to look for or monitor a prolactinoma. ARUP Laboratories lists 2.8 to 29.2 ng/mL for women and 2.1 to 17.7 ng/mL for men; pregnancy runs far higher.
What does the prolactin test measure?
Prolactin is made by the pituitary gland. Its main role is to signal breast tissue to grow during pregnancy and make milk after birth. MedlinePlus
Why is the prolactin test ordered?
- To help diagnose or monitor a prolactinoma, a pituitary tumor that makes prolactin. MedlinePlus
- To find the cause of irregular periods, infertility in men and women, milk production without pregnancy, or low sex drive and erectile dysfunction in men. MedlinePlus
What are typical prolactin ranges?
ARUP Laboratories publishes prolactin by sex, with separate notes for pregnancy and menopause. ARUP Laboratories
Reference ranges differ between laboratories and testing methods, and many also differ by age, sex, pregnancy or the phase of the menstrual cycle. The range printed on your own report is the one that applies to your result, and a clinician interprets it alongside your history.
| Group | Reference interval |
|---|---|
| Men, 10 years and older | 2.1 to 17.7 ng/mL |
| Women, 10 years and older | 2.8 to 29.2 ng/mL |
| Postmenopausal | 1.8 to 20.3 ng/mL |
| Pregnancy | 9.7 to more than 200.0 ng/mL |
What can affect prolactin results?
- Prolactin changes through the day, so the draw is usually scheduled three to four hours after waking. MedlinePlus
- Certain medicines and vitamins can affect prolactin; you may also be asked to fast. MedlinePlus
- Hypothyroidism, kidney disease, cirrhosis and PCOS can also raise prolactin. MedlinePlus
When should you talk to a clinician about a prolactin result?
- A provider considers symptoms, sex, history and the results of other tests, and decides whether more testing is needed. MedlinePlus
DiscoverMedica explains what a test measures and what named sources publish. It does not interpret individual results; the clinician who ordered your test, or one you choose, does.
Where can you get a prolactin test?
A clinician can order it as part of routine or follow-up care. Some services also let you order lab tests yourself; check that a service’s panel includes this marker, which laboratory runs it, and who reviews the result with you.
- Function HealthAnnual membership for broad lab panels, drawn at Quest sites or at home.
- Quest HealthOrder individual lab tests from Quest Diagnostics online, without a doctor’s visit.
Prolactin Test: questions, answered
What is a normal prolactin level?
ARUP Laboratories lists 2.8 to 29.2 ng/mL for women and 2.1 to 17.7 ng/mL for men aged 10 and older, 1.8 to 20.3 ng/mL after menopause, and from 9.7 to over 200 ng/mL in pregnancy. Other labs use their own ranges. Pregnancy and breastfeeding raise prolactin normally, so tell the person ordering the test if either applies.
What can raise prolactin besides a tumor?
MedlinePlus lists hypothyroidism, kidney disease, cirrhosis, PCOS and diseases of the hypothalamus, and notes that certain medicines and vitamins can affect levels. Pregnancy and breastfeeding raise prolactin normally. Your provider decides whether more tests are needed. Mention any medicines and vitamins you take.
When should a prolactin test be done?
Prolactin varies through the day, so MedlinePlus says the blood draw is usually scheduled three to four hours after you wake up. You may also be asked to fast. Follow the instructions from whoever orders it. Tell the person ordering it about medicines and vitamins, which can affect levels.
Sources
Last reviewed October 7, 2026. Every source above was checked on or before that date. Educational information only, not medical advice; it does not replace a conversation with a licensed clinician. DiscoverMedica does not employ clinicians.