Metanephrines, Fractionated, Free, LC/MS/MS, Plasma
Fasting Required: Overnight fasting is preferred

Specimen: Blood

Results: 7-10 Business Days

Includes: Metanephrine, Normetanephrine, and Total Metanephrine

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

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.

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

Description: This test can help diagnose or rule out an adrenal tumor called a pheochromocytoma or a rare extra-adrenal tumor, paraganglioma. These type of tumors produce excess hormones called catecholamines, which are broken down to metanephrines.

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.

Note: Result turnaround times are an estimate and are not guaranteed. Our reference lab may need additional time due to weather, holidays, confirmation/repeat testing, or equipment maintenance.