Investigation of galactorrhoea.
Investigation of amenorrhoea, infertility or hypogonadism. Raised prolactin levels are (often without galactorrhoea) associated with impaired gonadal function.
Differential diagnosis of pituitary fossa enlargement. Many "non-functioning" pituitary tumours in males and females are prolactin-secreting adenomas. Prolactin estimations are important in assessing the response to pituitary surgery, radiotherapy and drugs such as bromocriptine or cabergoline.
Assessment of hypothalamic-pituitary function. Basal prolactin concentrations may be raised in some patients with hypothalamic disorders such as craniopharyngioma. TRH and chlorpromazine stimulation have been used to further demonstrate abnormalities in prolactin secretion. The results are variable, and these tests are not recommended as a routine.
Patient should be unstressed but need not be fasting. Morning samples preferred. Because prolactin secretion is pulsatile, it is often desirable to take three samples at 20 minute intervals.
It is essential to state the medication that the patient is receiving, especially phenothiazine derivatives, aldomet, metoclopramide and oral contraceptive preparations etc.
A statement of the menstrual history and presence or absence of galactorrhoea is also necessary.
Ambient (8 - 24 degrees Celsius)
If overnight - Chilled (2 - 8 degrees Celsius)
Refer to Hyperprolactinaemia and Macroprolactin Information.
Prolactin Series Test Protocol
Changes in prolactin levels may occur seasonally (highest in spring) and across the day (circadian rhythm); nocturnal surges have been reported.
Female: 50 – 550 mIU/L
Male: 50 – 350 mIU/L
Two-site immunometric assay on Beckman Coulter ACCESS analyzer
$21.01 (Exclusive of GST)
Serum or lithium heparin plasma is preferred because the results on samples collected in full EDTA tubes may be up to 5% lower than for serum.
WARNING: Incomplete filling of EDTA tubes will cause gross underestimation of prolactin levels.