Prolactin Blood Test: Introduction, Test Result, Unit, Normal Range, Test Method, Clinical Significance, and Keynotes

Introduction of Prolactin Blood Test

A prolactin (PRL) blood test or prolactin test or PRL test measures the level of prolactin in the blood and it is a hormone synthesized by the pituitary gland. This hormone is responsible for the breasts to grow and make milk during pregnancy and after birth. PRL levels are normally high in pregnant women and new mothers whereas levels are normally low in nonpregnant women and men. A prolactinoma (tumor of the pituitary gland) causes a high level of PRL secretion. The excess level of this hormone can cause the production of breast milk in men and in women who are not pregnant or breastfeeding. In women, too much prolactin can also cause menstrual problems and infertility. In men, it can lead to lower sex drive and erectile dysfunction (impotence).

Test Result, Unit, Normal Range, Test Method, and Clinical Significance of Prolactin Blood Test

Keynotes on PRL Blood Test

• Prolactinoma is usually a benign tumor (non-cancerous). But when it is left untreated, these tumors can damage surrounding tissues.
• PRL test uses for-

1. Diagnose a prolactinoma
2. To find out the cause of a woman’s menstrual irregularities or infertility
3. Finding the cause of a man’s low sex drive or erectile dysfunction

• The symptoms of prolactinoma are-

1. Production of breast milk other than pregnancy and breastfeeding
2. Nipple discharge
3. Headaches
4. Changes in vision

• If you are taking medicine for birth control (pills), high blood pressure, and depression, share with your clinician (doctor) because these drugs may cause a high level of prolactin formation.
• Prolactin level changes throughout the day and it is the highest in the early morning. Three to four hours after waking up is the recommended time period for PRL testing. Blood is drawn for the assay just like the routine blood test like blood sugar and blood creatinine.

Further Reading

1. https://www.ncbi.nlm.nih.gov/books/NBK507829/
2. https://emedicine.medscape.com/article/2089400-overview
3. https://medlineplus.gov/lab-tests/prolactin-levels/
4. https://www.webmd.com/a-to-z-guides/prolactin-test