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Prolactin Level Test
Prolactin (also called PRL or lactogenic hormone) is a hormone produced by the pituitary gland in the brain. It plays an important role in repr...

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Understanding Prolactin and the Prolactin Test

Prolactin (also called PRL or lactogenic hormone) is a hormone produced by the pituitary gland in the brain. Prolactin plays an important role in the reproductive health of both women and men. Its main role, however, is to stimulate the production of milk in women after childbirth. In other words, prolactin triggers lactation. The specific function of prolactin in men is not well known, although levels of prolactin have been found to be a measure of sexual satisfaction in both men and women.

Why Is the Prolactin Test Done?


In women, a prolactin test may be ordered if she displays symptoms of prolactinoma, which is a benign (non-cancerous)tumor on the pituitary glandthat produces high levels of prolactin. Symptoms of prolactinoma can include:

  • unexplained headaches
  • visual impairment
  • lactation not associated with childbirth or nursing (called galactorrhea)

In cases of prolactinoma, the test is carried out regularly to check the tumor’s response to treatment.

The prolactin test can also be performed if a woman is having infertility problems or irregular menstrual periods and also to rule out problems with the pituitary gland or hypothalamus.


In men, the test may be carried if he displays the symptoms of prolactinoma, which include:

  • unexplained headaches
  • visual impairment
  • reduced sex drive or infertility problems

The test may also be used to

  • investigate testicular dysfunction or erectile dysfunction
  • rule out problems with the pituitary gland or hypothalamus

How Is the Test Carried Out?

A prolactin test is a blood test like any other. It can be performed at your doctor’s office or in a lab and takes just a few minutes. No test preparation is needed, but the sample is typically collected three to four hours after waking up in the morning.

Like any other simple blood test, blood will be drawn from a vein in your arm. Apart from a slight pinch during insertion and some mild soreness afterward, there is no pain involved.

Factors that may affect the test results include: certain medications, such as some birth controls pills, high blood pressure drugs, or antidepressants. Be sure to tell your healthcare provider about any medications you’re taking before the test is done. Sleeping problems, high stress levels, and strenuous exercise before the test could also influence the results.

What Are the Risks?

As with most blood tests, there is little risk of complications from the prolactin test. Once your blood is drawn, you might get a small bruise at the puncture site. Keep pressure on the site for a few minutes after the needle is removed to help reduce the risk of bruising. You may feel faint or lightheaded.

In rare cases, the vein may become inflamed after the test. This condition, called phlebitis, can be treated with a warm compress applied to the site several times a day.

For people with bleeding disorders, there is a risk of continued bleeding. If you have bleeding or clotting problems, or if you are taking blood-thinning medications (such as aspirin or warfarin), be sure to inform your doctor before the test is performed.

What Are Normal Results?

Your healthcare provider will assess whether your results are normal based on many factors, including your general health. Prolactin values may vary slightly among different laboratories. As a guide, the following are normal results:

Women who are not pregnant

< 25 ng/mL

Women who are pregnant

34 to 386 ng/mL


< 15 ng/mL

ng/mL = nanograms per milliliter

What Do High Levels Mean?

Low levels of prolactin are usually of no concern in women and men. However, above average levels of prolactin, or hyperprolactinemia, can be an indication of a deeper problem. Hyperprolactinemia is found in about 10 percent of the general population.

High levels of prolactin are normal during pregnancy and after childbirth while the mother is nursing.However, other causes of hyperprolactinemia include liver disease, kidney disease, and hypothyroidism, which can cause enlargement of the pituitary gland and can be treated with appropriate thyroid hormone replacement therapy. High levels of prolactin can also be caused by pituitary tumors, which can be treated medically or surgically.

Written by: Joanna Goldberg and Tim Jewell
Edited by:
Medically Reviewed by: Alan Carter, PharmD
Published: Aug 15, 2012
Published By: Healthline Networks, Inc.
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