What it measures
Prolactin is a hormone made by the pituitary gland at the base of the brain. It is best known for its role in making breast milk after birth, but men and women both make it. The test measures how much is in the blood.
Why people test it
- Measured when periods become irregular or stop, or with milky nipple discharge outside pregnancy.
- Checked in men and women with low sex drive, erection problems or fertility problems.
- Monitored on some medicines known to raise prolactin, such as certain antipsychotics.
- Often part of the baseline bloods before TRT, as high prolactin is one cause of low testosterone.
Typical range
Ranges vary between labs, with the method used, age and sex, and your report shows the lab's own range. Prolactin ranges differ more than most from lab to lab, so a result is best read against the range printed with it.
Finger-prick or vein?
A vein draw is usually advised, as for other hormone tests. Prolactin is often tested alongside testosterone, and gels or creams on the fingers can contaminate a finger-prick sample.
Stress can raise prolactin for a short time, so a result taken under stress can read high.