Prolactin Test

A prolactin test, also known as the PRL test, is used to measure the amount of prolactin, a hormone released by the pituitary gland. The test uses a blood sample to determine your prolactin level, which is present in both women and men. Elevated levels of prolactin can be found in those with pituitary tumors, thyroid conditions and kidney disease.

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What is prolactin?

Prolactin in a hormone in the bloodstream released by the pituitary gland in your brain. For women, prolactin works to stimulate breast development and milk production when pregnant or nursing. High prolactin levels in men can lead to low testosterone.

Why is a prolactin test important?

No preparation is necessary before taking the prolactin test. High levels of prolactin can indicate a wide range of conditions that are treatable with medication. Seek advice from a healthcare provider if you are experiencing any of the following symptoms linked to high prolactin levels:

Breast milk production in a woman who is not pregnant or nursing
Enlarged breasts in men
Lower sex drive
Impotence or erectile dysfunction
Irregular menstruation
Vision changes

In addition to a prolactin test, your healthcare provider may also test other hormone levels or order an MRI of the brain.

What do prolactin test results mean?

The normal prolactin level range for the prolactin test varies by gender. The values are measured in nanograms per milliliter of blood (ng/mL). The normal ranges are:

Men: 1–18 ng/mL
Non-pregnant women: 2–29 ng/mL
Pregnant women: 2–209 ng/mL

High prolactin levels could point to a number of conditions, including:

Hypothalamic disease
Hypothyroidism
Kidney disease
Prolactinoma, or a benign pituitary tumor
Other pituitary tumors or conditions

Some medications, especially psychiatric medicines, can elevate your prolactin levels. Stress and recent strenuous exercise can also lead to an increased prolactin level. Ask your healthcare provider to explain your test results. Your provider may ask for one random sample or a 24-hour urine sample. Your healthcare provider may ask you to avoid exercise before your test.