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PTD - 284

Test Directory - Prolactin

Clinical Indications

Prolactin should be measured as part of investigations into loss of libido, infertility, menstral disturbances and gynaecomastia. Prolactin-secreting tumours can present with visual disturbance, headache etc.

The use of prolactin levels in providing supportive evidence for a genuinely epilepetic seizure is severely limited by the need for a sample within 30 minutes of the fit.

Elevated prolactin levels may occur due to (the 5 Ps):

  • Physiological - stress, exercise, lactation, pregnancy

  • Pharmacological - drugs, especially neuroleptics, antiemetics, SSRI's

  • Pituitary - prolactinoma or other tumour causing stalk compression

  • Non-Pituitary - PCOS, hypothyroidism, renal failure

  • Problems - Macroprolactin (non-pathological increase in apparent prolactin)

Request Form

Combined Pathology blood form (Yellow/Black)


On request.

Turnaround Time

Same day

Patient Preparation

None required.




2 ml


Yellow top (SST) tube or

Paediatric orange top (lithium-heparin)

Causes for Rejection

Unlabelled sample

Reference Range

Less than 500 mU/L. All first occasion samples with prolactin levels above 500 mU/L will be screened for presence of Macroprolactin.


Prolactin levels above 500 mU/L (if macroprolactin screen negative) or calculated monomeric prolactin levels above 500 mU/L (if macroprolactin screen positive) may be of pathological significance, but must be interpreted in the light of clinical details and drug therapy (see above)

Lab Handling


Processing: Analysed from primary tube and stored at 4�C in the cold room (CB23)

Version 1.0 / July 2014                                                                                                            Approved by: Consultant Biochemist