1 SST/1.0 mL serum. After 30 minutes of clotting, promptly centrifuge and refrigerate.
Refrigerated: 2 weeks; Frozen: 6 months
Prolactin initiates and maintains lactation in females. It also plays a role in reulating gonadal function in both males and females. Prolactin increases during pregnancy and postpartum lactation. 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.