Prolactin, Reflex to Macroprolactin

TEST: 505990
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CPT: To be determined. Updates will be made when available.
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Special Instructions

If prolactin tests above reference range, testing will reflex to macroprolactin, performed at an additional charge.

If the patient's date of birth (DOB) and/or sex was not provided, testing will reflex to macroprolactin, independent of prolactin results.

Specimen Requirements

Specimen

Serum (preferred) or plasma, frozen

Volume

2.0 mL

Minimum Volume

1.0 mL (Note: This volume does not allow for repeat testing.)

Container

Serum from a gel tube; serum from red-top tube; serum transfer tube; plasma transfer tube or plasma from green-top tube

Collection

Prolactin: If a red-top tube or plasma is used, transfer separated serum or plasma to a plastic transport tube.

Macroprolactin: Do not draw sample until patient has been awake for at least two hours. Separate serum or plasma from cells within 45 minutes of collection. Transfer specimen to plastic transport tube before freezing. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.

Storage Instructions

Freeze.

Stability Requirements

Temperature

Period

Room temperature

14 days

Refrigerated

14 days

Frozen

6 months

Freeze/thaw cycles

Stable x6

Test Details

Use

Prolactin should be considered for work-up of galactorrhea (inappropriate lactation). A pituitary function test useful in the detection of prolactin-secreting pituitary tumors (microadenomas, macroadenomas) with or without galactorrhea, with or without structural evidence of sellar enlargement. An adult female premenopausal patient having amenorrhea and galactorrhea is highly suspect of pituitary prolactinoma and is a candidate for radiologic evaluation of the pituitary as well as serum prolactin levels. Elevated prolactin may be associated with corpus luteum insufficiency or anovulation. Sequelae of hyperprolactinemia include amenorrhea, anovulation and decreased bone density.

Monomeric prolactin, the bioactive form of prolactin, is used to assess true hyperprolactinemia not due to the presence of macroprolactin, which is prolactin bound to immunoglobulins, and has been shown to have low biological activity in vivo. Presence of macroprolactin should be checked in the context of asymptomatic hyperprolactinemia.

Methodology

ECLIA

References

Casanueva FF, Molitch ME, Schlechte JA, et al. Guidelines of the Pituitary Society for the diagnosis and management of prolactinomas. Clin Endocrinol (Oxf). 2006 Aug;65(2):265-723.16886971
Fahie-Wilson MN, Soule SG. Macroprolactinemia: contribution to hyperprolactinemia in a district general hospital and evaluation of a screening test based upon precipitation with polyethylene glycol. Ann Clin Biochem. 1997 May;34(Pt 3):252-258.9158821
Gibney J, Smith TP, McKenna TJ. Clinical relevance of macroprolactin. Clin Endocrinol (Oxf). 2005 Jun;62(6):633-643.15943822
Melmed S, Casanueva FF, Hoffman AR, et al. Diagnosis and treatment of hyperprolactinemia: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011 Feb;96(2):273-288.21296991
Mounier C, Trouillas J, Claustrat B, Duthel R, Estour B. Macroprolactinaemia associated with prolactin adenoma. Hum Reprod. 2003 Apr;18(4):853-857.12660284
Samson SL, Hamrahian AH, Ezzat S; AACE Neuroendocrine and Pituitary Scientific Committee; American College of Endocrinology (ACE). American Association of Clinical Endocrinologists, American College of Endocrinology Disease State Clinical Review: Clinical Relevance of Macroprolactin in the Absence or Presence of True Hyperprolactinemia. Endocr Pract. 2015 Dec;21(12):1427-1435.26642103
Vieira JG, Tachibana TT, Obara LH, Maciel RM. Extensive experience and validation of polyethylene glycol precipitation as a screening method for macroprolactinemia. Clin Chem. 1998 Aug;44(8 Pt 1):1758-1789.9702971

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