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Test Code LAB3279 Macroprolactin, Serum

Additional Codes


Reporting Name

Macroprolactin, S
Seattle Children's Hospital Note:

SCH Clinical System Name: Macroprolactin

Useful For

Determining biologically active levels of prolactin, in asymptomatic patients with elevated prolactin levels


Ruling out the presence of macroprolactin

Specimen Required

Patient Preparation: For 12 hours before specimen collection do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.


Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 1 mL

Collection Instructions: Spin down and separate serum from clot.

Seattle Children's Hospital Note:

Collect 2.0 mL whole blood in a Red top.

Specimen Type


Specimen Minimum Volume

0.6 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 7 days
  Frozen  90 days
  Ambient  24 hours

Day(s) Performed

Monday through Sunday

Seattle Children's Hospital Note:

TAT: 3 - 5 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Method Name

TOPRL: Electrochemiluminescent Immunoassay

PEGPR: Polyethylene Glycol (PEG) Precipitation Followed by Electrochemiluminescent Immunoassay

Method Description


The Roche cobas e immunoassay Prolactin II method employs 2 monoclonal antibodies specifically directed against prolactin. A biotinylated monoclonal antibody and a second monoclonal antibody labeled with a ruthenium complex react with prolactin in the sample to form a sandwich complex. After the addition of streptavidin-coated microparticles, the complex becomes bound to the solid phase via interaction of biotin and streptavidin. Application of a voltage to the electrode then induces chemiluminescent emission, which is measured.(Package insert: Elecsys Prolactin II, V 8.0, Roche 2017)



Macroprolactin and oligomers can be precipitated by using a 25 % aqueous PEG solution (ratio 1+1). After centrifugation, the supernatant containing monomeric prolactin is used in the Elecsys Prolactin II assay in the same way as a native sample. The dilution effect which occurs during sample pretreatment and the coprecipitation of monomeric prolactin must be taken into consideration. Precipitated prolactin is calculated by subtracting the unprecipitated prolactin value from the total prolactin. The percentage of precipitated prolactin to total prolactin indicates the presence or absence of macroprolactin.(Package insert: Elecsys Prolactin II, V 8.0, Roche 2017)

Reference Values



<18 years: not established

≥18 years: 4.0-15.2 ng/mL


<18 years: not established

≥18 years: 4.8-23.3 ng/mL




<18 years: not established

≥18 years: 2.7-13.1 ng/mL


<18 years: not established

≥18 years: 3.4-18.5 ng/mL


When the percent of the precipitated (complexed) prolactin fraction of the total prolactin is 60% or less, the result is considered negative for macroprolactin.

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

84146 x 2

LOINC Code Information

Test ID Test Order Name Order LOINC Value
MCRPL Macroprolactin, S 78993-3


Result ID Test Result Name Result LOINC Value
PROU Prolactin,Unprecipitated,S 38926-2
T_PRL Prolactin,Total,S 20568-2
RATIO Prolactin, Percent PEG-precipitated 51441-4
CMT42 Interpretive Comment 48767-8

Profile Information

Test ID Reporting Name Available Separately Always Performed
TOPRL Prolactin,Total,S Yes, (order PRL) Yes
PEGPR Prolactin,Unprecipitated,S No Yes

Report Available

Same day/1 to 3 days

Reject Due To

Gross hemolysis Reject
Gross lipemia OK


If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen.

Seattle Children's Hospital Additional Information:

Aliases: Monomeric; PRL (Prolactin); Prolactin (PRL); Prolactin, Macro