How Does the Prolactin Test Work?


Prolactin is a hormone secreted by the Pituitary gland. The pituitary gland is located in the lower part of the brain and is responsible for various body functions. This hormone is secreted in males and females but at different levels. Males generally secrete less prolactin than females. Prolactin hormone levels increase manyfold during pregnancy. This hormone is mainly responsible for milk production in females during postpartum. Prolactin levels are at their peak two weeks after delivery. The levels come down if breastfeeding is stopped. If breastfeeding is continued, the prolactin levels remain high for six months.

What does the Prolactin test indicate?

If the prolactin levels are high, they may indicate the following disorders:

  • Pituitary gland disorders – This pea-sized gland is essential as it controls all other glands. If the pituitary gland is not functioning optimally, it can cause various symptoms. It can severely affect growth in kids as it releases growth hormones.
  • Thyroid disorders – The thyroid gland is also called the butterfly gland because of its shape. It is in the neck near the voice box. It is mainly responsible for the metabolism of the body. Prolactin tests can indicate problems with the Thyroid, specifically lower thyroid levels (Hypothyroidism).
  • Kidney disorders – Kidneys are located in the lumbar region. They remove waste through urine. High levels of prolactin can indicate kidney problems. For confirmation, other tests with blood and urine samples are done.
  • Liver disorders – The liver is the biggest internal organ in our body and performs several critical functions. If the liver functions are abnormal, it can be indicated through the Prolactin test. Liver disorders cause various symptoms, and doctors can order tests for liver function for confirmation.
  • Anorexia – It is an eating disorder related to an extreme diet. Anorexia is a physical disease stemming from a mental condition that almost compels patients to go hungry. Even individuals with optimum body weight go for extreme diets, and the prolactin test can help with the proper diagnosis.
  • Prolactinoma – Prolactinoma is a tumor of the pituitary gland. This tumor causes various symptoms as well as problems in normal body functions. The tumor position is very delicate as it is inside the brain. Early detection and treatment thereafter can be facilitated through the prolactin test. 
  • Shingles – Shingle is a skin infection caused by a virus. It has symptoms like rashes and blisters and causes pain. The prolactin test will confirm if the shingles are related to higher levels of Prolactin.
  • Cancer – In some cases, cancers cause prolactin levels to go up. Prolactin tests in conjunction with other tests can help the doctor form a proper diagnosis. Lung, kidney, and liver cancer can cause prolactin levels to rise, disrupting body functions.
  • Stress – Stress has become a regular part of our lives. It causes various physical and mental disorders. Stress management has become a requirement. A prolactin test can confirm if the body is producing high prolactin levels. Further tests can indicate if the cause of the high levels is stress. 

Prolactin test procedure

A blood test checks the prolactin levels and is done within 2 hours of waking up. The Prolactin levels are at their peak during the morning. The sample is collected and sent to the lab for analysis. The results of the prolactin test are available in 2-7 days. It does not require fasting. The doctor may advise medicine discontinuation just before the test for a short while. It is best to avoid strenuous physical activities at least thirty minutes before the test. Stress may affect the results, hence relaxing physically and mentally is advisable for accurate test results.

Prolactin tests normal levels

Normal levels of prolactin indicate fertility in both men and women. Abnormal levels of prolactin can cause Galactorrhea in men – a milky discharge from the nipples. Lack of milk production in new mothers is related to lower prolactin levels.

  • Anything less than 17ng/ml and more than two ng/ml is normal levels of prolactin in men. (ng/ml is nanograms per milliliter).
  • Anything less than 25ng/ml and more than two ng/ml is normal for non-pregnant women.
  • Anything between 10 and 209 ng/ml is normal for pregnant women.


Prolactin tests can give insights into various things. Testing in a reputed lab will give accurate results and help with a proper diagnosis. As seen above, doctors may prescribe other tests with prolactin tests. The test is essential to ascertain the exact levels of prolactin and correlate them with the symptoms. If you find any signs of higher prolactin, you should consult your doctor for a comprehensive diagnosis. 

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