Prolactin
Also known as: Serum prolactin, PRL test, prolactin test, prolactin zyada hona
Prolactin is a hormone from the pituitary gland that makes breast milk after childbirth. High levels at other times can affect periods and fertility.
Why it's ordered
Irregular or missed periods, infertility, milk discharge from the breasts without pregnancy, low sex drive or erectile problems, and some headaches or eyesight problems.
Preparation
Best taken in the morning after resting for a while. Avoid breast or nipple stimulation and intense exercise just before the test. Tell your doctor about all medicines.
Typical adult values
| Women (not pregnant) | below about 25 ng/mL |
|---|---|
| Men | below about 15–20 ng/mL |
Ranges vary between labs and methods. Always use the range printed on your report.
If it's high
Common causes are pregnancy, breastfeeding, stress, an underactive thyroid, kidney disease and medicines such as some anti-sickness drugs (metoclopramide, domperidone) and antipsychotics. Very high levels make a small pituitary tumour (prolactinoma) more likely; these are usually not cancer and are treatable with tablets.
If it's low
Low prolactin is uncommon and usually not important.
Good to know
A mildly high result is often repeated, because stress from the blood test itself can raise prolactin. Some people have 'macroprolactin', an inactive form that raises the result without causing symptoms; labs can test for it.
Common questions
What is a normal prolactin level?
Typically below about 25 ng/mL in women who are not pregnant, and below about 15–20 ng/mL in men. Always use the range printed on your report.
Can medicines raise prolactin?
Yes, for example some anti-sickness drugs (metoclopramide, domperidone) and antipsychotics.
Why is a high prolactin repeated?
Stress from the blood test itself can raise prolactin, so a mildly high result is often repeated.
Is a prolactinoma cancer?
Usually not. These small pituitary tumours are treatable with tablets.