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Prolactin level

Prolactin hormone measurement — for evaluation of milk secretion, menstrual irregularities, and the pituitary gland.

Measurement of prolactin hormone secreted by the pituitary gland in the blood. Used in the evaluation of menstrual irregularities, infertility, and milk leakage (galactorrhea).

Indication

  • Menstrual irregularities or absence of menstruation (amenorrhea)
  • Milk leakage in women outside of pregnancy (galactorrhea)
  • Evaluation of unexplained infertility
  • Decreased libido, erectile dysfunction, or breast enlargement (gynecomastia) in men
  • Suspicion of pituitary adenoma (pituitary gland tumor)
  • Headache accompanied by visual field loss
  • Monitoring the effect of certain medications (antipsychotics, antidepressants) on hormone levels

Preparation

  • The blood sample is taken in the morning, preferably between 08:00 and 10:00
  • At least 30 minutes of quiet rest is required before sample collection (stress and exercise cause falsely high results)
  • Breast examination or breast stimulation should not be performed before the test
  • Fasting is generally not required; however, some laboratories recommend 8 hours of fasting
  • Medications used (especially psychiatric drugs and stomach medications) should be reported to the doctor

How it's performed

  1. The patient is rested in the laboratory waiting area for at least 30 minutes
  2. A suitable vein is identified in the arm and the skin is wiped with antiseptic
  3. Approximately 3-5 mL of venous blood is drawn into a vacuum tube
  4. The tube is labeled and sent to the laboratory
  5. Prolactin level is measured by chemiluminescence or electrochemiluminescence
  6. The result is reported in ng/mL or mIU/L

Post-procedure

  • Results are generally available the same day
  • In high values, a macroprolactin screening test may be requested for the actual prolactin level
  • If significantly elevated, a pituitary MRI is planned
  • If treatment has been started, a follow-up measurement is recommended after 4-6 weeks
  • Results must always be evaluated by the physician together with the clinical picture

Risks

  • Temporary bruising or tenderness at the blood draw site
  • Rarely dizziness or temporary weakness (vasovagal response)
  • Very rare risk of infection
  • Falsely high values due to stress, exercise, pregnancy, and breast stimulation

FAQ

Do I need to fast before the test?

Fasting is not mandatory. However, the most important rule is to provide the sample in the morning hours after at least 30 minutes of rest. Stress and exercise can elevate the value.

Does high prolactin always mean disease?

No. Pregnancy, breastfeeding, stress, sleep, sexual intercourse, certain medications, and even breast stimulation can elevate prolactin. A single elevated result is not diagnostic on its own.

How long does it take to get results?

In most laboratories, results are ready the same day, within 2-4 hours.

Is prolactin measurement also necessary in men?

Yes. In men, prolactin is also evaluated in cases of decreased libido, erectile dysfunction, infertility, or breast enlargement.