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

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

METF or 19548

Metanephrine; Normetanephrine

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

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

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

Refrigerated.

After separation from cells: Room temperature: 24 hours; Refrigerated: 14 days; Frozen: 30 days

Heparinized plasma. Serum. CSF. Urine.

Monday - Saturday

2-3 days (From receipt at performing laboratory)

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.

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

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.