Prolactin Serum Test (S Prolactin Test)

Serum prolactin test

It is a simple blood test that measures prolactin levels in blood. Prolactin is a hormone which is secreted by pituitary gland present in the brain. This hormone plays an important role during pregnancy and after delivery in females. It is responsible for breast growth and production of milk in breasts during pregnancy and after delivery. Prolactin serum levels are higher than normal during pregnancy and during lactation period. However its levels are in normal range in nonpregnant females and in males.

If serum prolactin levels are abnormally high in nonpregnant females it may cause various symptoms like production of milk from breasts(called as galactorrhea), menstrual irregularities, and difficulty in getting pregnant. If the levels are high in males it may cause erectile dysfunction, decrease libido and impotence.

The high prolactin levels in blood is because of presence of a type of tumour called as prolactinoma .it is a tumour of pituitary gland which cause excessive production of prolactin. These tumours are usually noncancerous but if allowed to increase in size they may destroy the surrounding healthy tissue. Along with above mentioned symptoms due to high prolactin levels other symptoms of prolactinoma are headache, visual disturbances, and excessive acne and abnormal increase in facial and body hair

Sometimes high prolactin levels may also cause hypothyroidism where there is deficiency of thyroid hormone.

Why is serum prolactin test prescribed?

Your healthcare provider may ask for this test in following conditions:

• Presence of symptoms such as breast secretion/discharge, irregular menses, difficulty in conception in females
• Presence of symptoms such as low sex drive, erectile dysfunction in males
• Monitor response to treatment of prolactinoma

Procedure and prerequisites

The sample for prolactin serum test is taken from blood by inserting a small needle into vein of your arm. A small amount of blood is then collected in test tube or vial. You may feel some pain due to needle prick. You should take this test three to four hours after getting up in morning. Certain medications may alter the prolactin levels such as birth control pills, antidepressants so consult your doctor before undertaking this test. Overnight fasting is preferred before the test.

Reference range

Normal range males-less than 15 ng/ml

Nonpregnant females-less than 25 ng/ml

Pregnant females-80-400 ng/ml