Metanephrines, Fractionated, Free, LC/MS/MS, Plasma

Test Code
19548

CPT Codes
83835

Includes
Metanephrine, Normetanephrine, and Total Metanephrine

Preferred Specimen
2.5 mL plasma collected in an EDTA (lavender-top) tube

Patient Preparation
Patient should avoid alcohol, coffee, tea, tobacco and strenuous exercise prior to collection. Overnight fasting is preferred. Patients should be relaxed in either a supine or upright position before blood is drawn.

Minimum Volume
1.5 mL

Instructions
Draw specimen in a pre-chilled EDTA lavender-top Vacutainer®. The whole blood sample should be kept on wet ice until centrifuged (preferably at 4° C) to separate the plasma within 2 hours of venipuncture. After centrifugation, the plasma should be transferred to a plastic, leak-proof vial and immediately refrigerated.

Transport Container
Plastic screw-cap vial

Transport Temperature
Refrigerated (cold packs)

Specimen Stability
Room temperature: 4 hours
Refrigerated: 14 days
Frozen: 14 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Heparinized plasma • Serum • CSF • Urine

Methodology
Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS)

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule
Set up: Mon-Sat a.m.; Report available: 2 days

Limitations
False-positive results have been observed in patients with either chronic kidney disease or hypertension.

Reference Range
  Reference Range  
Metanephrine, Free ≤57 pg/mL
Normetanephrine, Free    ≤148 pg/mL
Total, Free (MN+NMN) ≤205 pg/mL


Clinical Significance
Normetanephrine (NM) and metanephrine (MN) are the extra-neuronal catechol-o-methyl transferase (COMT) metabolites of the catecholamines norepinephrine and epinephrine, respectively. Measurement of plasma metanephrines is more sensitive (but may be less specific) than measurement of catecholamines for the detection of pheochromocytoma. Proper interpretation of results requires awareness of recent medication/drug history (e.g., antyhypertensive agents, alcohol, cocaine) and other pre-analytical factors (e.g., stress, severe congestive heart failure, myocardial infarction) that influence release of catecholamines and metanephrines.

Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153



The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.