Prolactin, Serum

What is Prolactin (Serum) Test?

Prolactin is a hormone produced by the pituitary gland. The serum prolactin test measures the amount of this hormone circulating in the blood.

Key Parameter

Why the Test is Done

• Routine check‑up for reproductive health
• Investigating unexplained infertility, amenorrhea, or menstrual irregularities
• Evaluating symptoms such as galactorrhea, headaches, or visual disturbances
• Monitoring treatment of pituitary disorders

Early Detection

This test can help identify signs of pituitary adenoma, hypothyroidism, or other endocrine disorders, but it does not diagnose them on its own. A clinician interprets the result with symptoms, history, and other investigations.

What Abnormal Results May Mean

• High prolactin: may indicate a prolactinoma, hypothyroidism, medication effect, or other pituitary lesions.
• Low prolactin: can occur in hypopituitarism, certain medications, or severe stress. Many factors—hydration, recent exercise, stress, certain drugs—can influence levels.

Who Might Need This Test

• Women with infertility or menstrual problems
• Men or women with unexplained galactorrhea
• Individuals with headaches, visual changes, or pituitary symptoms
• Patients on medications known to affect prolactin

Summary

The serum prolactin test measures a key pituitary hormone to help assess reproductive and endocrine health. Results guide further evaluation but are not definitive on their own.

Preparation

• Fasting: No fasting required.
• If combined with fasting tests: Follow the longest fasting period required among the tests.
• Procedure: A healthcare professional will draw a small amount of blood from a vein in your arm using a needle. The process takes about 5 minutes.
• Comfort: You may feel a brief pinch when the needle is inserted. The site may be slightly sore afterward.
• Precautions: Avoid alcohol and strenuous exercise 24 hours before the test. Inform your clinician about any medications you are taking, especially dopamine agonists, antipsychotics, or anti‑epileptics, as they can affect prolactin levels.
• Aftercare: Apply gentle pressure to the puncture site and keep it clean.

Please confirm specific preparation instructions with your doctor or the laboratory. This information is educational and not a substitute for professional medical advice.