Prolactin

5 mL blood in plain tube.

Physiological causes of increased prolactin (eg, stress, strenuous exercise, pregnancy, breast palpation, nipple stimulation) should be avoided prior to collection of specimen.

The specimen should be transported to the laboratory as rapidly as possible.

Immunoassay.

Method dependent - consult pathologist.

Female: < 750 mU/L

Male: 150-500 mU/L

Assessment of patients with a suspected pituitary tumour; investigation of infertility, amenorrhoea, galactorrhoea and impotence.

Increased levels are found in patients with prolactinomas and hypothalamic disorders, which may be associated with the amenorrhoea-galactorrhoea syndrome.

Some drugs cause increased levels, eg, phenothiazines, metoclopramide and oestrogens.

Increased levels occur during normal pregnancy and lactation.

Some methods may give falsely high values due to macroprolactin variants.