Metanephrines, Fractionated, Free, LC/MS/MS, Plasma : 19548

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

Test Code
METF or 19548

Alias/See Also
Metanephrine; Normetanephrine

CPT Codes
83835

Includes
Includes: Metanephrine, Free, Normetanephrine, Free, and Total, Free

Instructions
Patient should avoid alcohol, coffee, tea, tobacco and strenuous exercise prior to collection. Overnight fasting is preferred.

Collect in a pre-chilled Lavender (EDTA). Keep tube cold ( 2-8 C) after collection and process within two hours of collection per Specimen Preparation.

Transport Container
Centrifuge lavender within 2 hours and transfer 2.5 mL plasma into a standard transport tube, (Min: 1.5 mL).

Transport Temperature
Refrigerated.

Specimen Stability
After separation from cells: Ambient: 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)

Setup Schedule
Tuesday - Saturday

Report Available
3-4 days (From receipt at performing laboratory)

Limitations
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.

Reference Range
Metanephrine, Free: less than or equal to 57 pg/mL
Normetanephrine, Free: less than or equal to 148 pg/mL
Total, Free (MN + NMN): less than or equal to 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



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.