Laboratory Medicine Program

Metanephrines and 3-Methoxytyramine, Plasma
(3-MT, PFM, Normetanephrine)

Clinical Decription:
This test is useful as a screening test for presumptive diagnosis of catecholamine-secreting pheochromocytomas or paragangliomas. Pheochromocytomas and other tumors derived from neural crest cells (eg, paragangliomas and neuroblastomas) secrete catecholamines (epinephrine, norepinephrine, and dopamine). Metanephrine and normetanephrine (collectively referred to as metanephrines) are the 3-methoxy metabolites of epinephrine and norepinephrine, respectively. The metabolite of dopamine is 3-methoxytyramine. The metanephrines are stable metabolites and are cosecreted directly with catecholamines by pheochromocytomas and other neural crest tumors. This results in sustained elevations in plasma free metanephrine levels, making them more sensitive and specific than plasma catecholamines in the identification of pheochromocytoma patients.

Method: LC-MS/MS

Component Tests Used: n/a

Reference Ranges Used:
Metanephrine: < 0.50 nmol/L, Normetanephrine: < 0.90 nmol/L, 3-Methoxytyramine: < 0.30 nmol/L

Specimen Type: 7mL pink or lavender EDTA /5mL draw (x2)
Volume: 3 mL (minimum: 3 mL)

Shipping: frozen plasma

Special Instructions: Fasting is required. Patient must be in supine position for at least 30 minutes prior to specimen collection.

Testing Schedule(s): 10 Days.

Turnaround Time: 10 Business days

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For more information, call 416.340.5227 or 1.866.865.5227

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