An Overview of a Prolactin Blood Test

Prolactin is a hormone produced by the pituitary gland of the body. A pea-sized organ that’s found at the base of the brain, pituitary gland helps in controlling the metabolism, growth and sexual development of the body. Though prolactin is found in both men and women in small quantities, it’s majorly found in females who are pregnant and about to deliver a baby. The main purpose of this hormone is to stimulate lactation i.e. production of milk amid women during pregnancy and to maintain its supply post-delivery of the baby. A prolactin blood test helps in diagnosing problems caused by the hormone as well as measures the levels of this particular hormone in the bloodstream. The test also aids in the determination of the presence of a tumor called prolactinoma in the pituitary gland.

Symptoms of prolactinoma

Common symptoms of prolactinoma in women are as follows-

  • Unexplained headaches,
  • Visual Impairment,
  • Galactorrhoea or lactation outside of the childbirth or nursing,
  • Pain or discomfort during sex,
  • Abnormal ache, etc.

Common symptoms of prolactinoma in men are as follows-

  • Unexplained headaches,
  • Reduced sex drive,
  • Erectile dysfunction,
  • Visual impairment etc.

Why is the test done?

A prolactin test is done to check the following:-

  • Find out the reasons behind atypical discharge from a woman’s nipples or if she is unable to conceive (infertility).
  • Prolactin level is tested in males when a pituitary gland problem is suspected. The test is also performed to check the prolactin levels in men if they seem to lack sexual desire or face trouble in erection (called the erectile dysfunction). The test helps to rule out Hypothalamus in men as well.

How to prepare?

  • Before the test, one should avoid drinking or eating for a certain number of hours.
  • The prolactin blood test is usually performed 3 hours after one wakes up in the morning.
  • Any emotional stress or strenuous exercise should be avoided as it can raise the prolactin level in the blood. One is also asked to rest for 30 minutes before having the blood drawn.
  • One should avoid nipple stimulation for 24 hours before prolactin test as it can increase the prolactin level in the bloodstream.

How is it done?

  • An elastic band is encircled around the upper arm to stop the flow of blood. This makes the veins look larger and hence, easier for a nurse or a technician to draw blood.
  • The needle site is fist cleaned with an alcohol swab and then a needle is injected into the vein.
  • A small quantity of blood is extracted from the vein.
  • Once enough blood is collected, the band around the arm is removed.
  • A cotton and bandage are tied on the punctured site to stop the outflow of blood.


The normal values of a prolactin test in-

  • Non-pregnant women should range between 4 and 23 nanograms per milliliter.
  • Expectant mothers should range between 34 and 386 nanograms per milliliter.
  • Men should range between 3 and 15 nanograms per milliliter.
  • Children should range between 3.2 and 20 nano grams per milliliter.

High levels of prolactin in the blood indicate the presence of a tumor in the pituitary gland. It also means that pituitary gland is making excess prolactin for some unknown reason like – idiopathic hyperprolactinemia, etc. Other severe conditions that can cause high prolactin levels in the blood include liver disease (Cirrhosis), kidney disease and hypothyroidism.


Treatment against pituitary tumour typically includes taking medications such as bromocriptine, complete removal of the pituitary gland and radiation therapy. The type of treatment given to a patient is based on the size of the tumour, health and the age of the person being treated.

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