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Test Code LAB5118 Metanephrines, Fractionated, Free, Plasma

Important Note

Mayo's test code: PMET

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Reporting Name

Metanephrines, Fract., Free, P

Specimen Type

Plasma EDTA


Specimen Required


Patient Preparation: Use of an Epi-pen within the last 7 days may produce inaccurate results.

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube: Lavender top (EDTA)

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions: Within 2 hours of collection centrifuge and aliquot plasma into a plastic vial.


Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Specimen Stability Information

Specimen Type Temperature Time
Plasma EDTA Frozen (preferred) 28 days
  Refrigerated  14 days
  Ambient  7 days

Specimen Minimum Volume

0.3 mL

Day(s) Performed

Monday through Saturday

Specimen Retention Time

2 weeks

Report Available

2 to 5 days

Reference Values

METANEPHRINE, FREE

<0.50 nmol/L

 

NORMETANEPHRINE, FREE

<0.90 nmol/L

Useful For

Screening test for presumptive diagnosis of catecholamine-secreting pheochromocytomas or paragangliomas

CPT Code Information

83835

LOINC Code Information

Test ID Test Order Name Order LOINC Value
PMET Metanephrines, Fract., Free, P 57772-6

 

Result ID Test Result Name Result LOINC Value
10140 Normetanephrine, Free 40851-8
10139 Metanephrine, Free 49700-8

Method Description

Free metanephrine (MN) and normetanephrine (NMN) are extracted from plasma using solid phase extraction. The concentrated eluate is analyzed using liquid chromatography tandem mass spectrometry and quantified using stable isotope labeled internal standards, d3-MN and d3-NMN . Analytes and internal standards are ionized using electro spray ionization and are detected in the multiple reaction-monitoring mode. The specific transitions for MN, NMN, d3-MN, and d3-NMN are m/z 180.2 to m/z 148.2, 166.2 to m/z 134.2, 183.2 to m/z 151.2, and m/z 169.2 to m/z 137.2, respectively.(Unpublished Mayo method)

Supportive Data

This liquid chromatography tandem mass spectrometry (LC-MS/MS) method replaces the in-house high-performance liquid chromatography with electrochemical detection (HPLC-EC) method. The HPLC-EC method was labor intensive, with a complicated extraction and lengthy run time, and was prone to interferences. The LC-MS/MS method correlates well with Mayo Clinic Laboratories previously performed HPLC-EC method: N=92, slope=0.87, intercept=0.05, r(2)=0.95. The reference ranges remain the same as the HPLC-EC method and were validated by method comparison between these methods. LC-MS/MS also correlates with the National Institutes of Health's HPLC-EC method.

Forms

If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-General Request (T239)

-Oncology Test Request (T729)

-Renal Diagnostics Test Request (T830)