Preferred Specimen(s) 1 mL serum
Transport Container Plastic screw-cap vial
Transport Temperature
- Ambient, stable 7 days,
- Refrigerated 14 days
Reject Criteria
- Gross hemolysis
- Grossly icteric
- Grossly lipemic
Methodology Chemiluminescence
Clinical Significance Prolactin is a single-chain polypeptide hormone secreted by the anterior pituitary under the control of prolactinreleasing factors. These inhibiting and releasing factors are secreted by the hypothalamus. Prolactin is also synthesized by the placenta and is present in amniotic fluid. Prolactin initiates and maintains lactation in females. It also plays a role in regulating gonadal function in both males and females. In adults, basal circulating prolactin is present in concentrations upto 30 ng/mL. During pregnancy and postpartum lactation, serum prolactin can increase 10- to 20-fold. Exercise, stress, and sleep also cause transient increases in prolactin levels. Consistently elevated serum prolactin levels greater than 30 ng/mL, in the absence of pregnancy and postpartum lactation, are indicative of hyperprolactinemia, which is the most common hypothalamic-pituitary dysfunction encountered in clinical endocrinology. Hyperprolactinemia often results in galactorrhea, amenorrhea, and infertility in females, and in impotence and hypogonadism in males. Renal failure, hypothyroidism, and prolactin-secreting pituitary adenomas are also common causes of abnormally elevated prolactin levels.