Plasma Metanephrine Adrenal Test - Plasma Metanephrine Test

This biochemical assay measures the plasma levels of metanephrines, specifically metanephrine (MN) and norepinephrine (NMN). These compounds are inactive metabolites of the catecholamine hormones (adrenaline and noradrenaline) that are continuously produced by pheochromocytoma and other chromaffin cell tumors. Measuring free plasma metanephrine is the most sensitive test (up to 99%) for detecting these tumors, as it better reflects the tumor's continuous active secretion than measuring native catecholamines.