Ordering Recommendation

First-line test in suspected pheochromocytoma.

Mnemonic
META PF
Methodology

Quantitative Liquid Chromatography-Tandem Mass Spectrometry

Performed

Sun-Sat

Reported

2-4 days

New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation

Drugs and medications may affect results and should be discontinued for at least 72 hours prior to specimen collection, if possible. Collection of the specimen after the patient has rested for 15 minutes in a supine position is recommended.

Collect

Lavender (EDTA), pink (K2EDTA), or green (sodium or lithium heparin).

Specimen Preparation

Centrifuge within 1 hour. Transfer 2 mL plasma to an ARUP Standard Transport Tube and freeze immediately. (Min: 1 mL) Avoid hemolysis.

Storage/Transport Temperature

Frozen. Separate specimens must be submitted when multiple tests are ordered.

Unacceptable Conditions

Plasma separator tubes. Body fluids other than EDTA or heparinized plasma. Non-frozen specimens.

Remarks
Stability

After separation from cells: Ambient: Unacceptable; Refrigerated: Unacceptable; Frozen: 1 month

Reference Interval

Normetanephrine: 0.0-0.89 nmol/L
Metanephrine: 0.0-0.49 nmol/L

Interpretive Data

This test is useful in the detection of pheochromocytoma, a rare neuroendocrine tumor. The majority of patients with pheochromocytoma have a plasma normetanephrine concentration in excess of 2.2 nmol/L and/or a metanephrine concentration in excess of 1.1 nmol/L. Increased concentrations of these analytes serve as confirmation for diagnosis. Patients with essential hypertension and plasma concentrations of normetanephrine below 0.9 nmol/L and a metanephrine concentration below 0.5 nmol/L, can be excluded from further testing. If clinical suspicion remains, repeat testing or testing for metanephrines in a 24-hr. urine specimen should be considered.

Compliance Category

Laboratory Developed Test (LDT)

Note

Isoetharine, isoproterenol, 3,4-methylenedioxyamphetamine (MDA), and 3,4-methylenedioxymethamphetamine (MDMA) are known to interfere in this test.

Many drugs/medications, including over-the-counter and herbal products, can interfere with test results. Testing for all potential interactions is not possible.  If the patient is taking a drug not listed as an interferent, its potential effect on test results is unknown. If test results are inconsistent with clinical evidence, drug interference should be considered. If appropriate, the patient should discontinue the potential interferent for 48-72 hours and a new sample collected for retesting.

Hotline History
N/A
CPT Codes

83835

Components
Component Test Code* Component Chart Name LOINC
0050189 Normetanephrine 25489-6
0050191 Metanephrine 25474-8
0050192 Metanephrines Interpretation 48767-8
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • Fractionated metanephrines
  • Fractionated Plasma Free Metanephrines
  • Free Metanephrine
  • Metanephrine
  • Metanephrines, Fractionated
  • NMN, plasma
  • Normetanephrine
  • Normetanephrine, free
  • Plasma Metanephrines
  • Quantitative Metanephrines
Metanephrines, Plasma (Free)