The Metanephrine - Plasma test diagnoses: if you are suffering form adrenal tumor which is called phyeochromocytoma, if you are suffering from extra-adrenal tumor which is called paraganlioma. The test basically measures the amount of Metanepherine presence in your blood for over a period of 24 hours.
Paraganglioma and Pheochromocytoma are responsible for producing large amounts of catecholamines and metabolites. It results in increased concentrations of catecholamines and metabolites in blood and urine.
Catecholamines are produced in the internal area of adrenal glands. It is caused due to the formation of metanephrines which helps to break down hormones in the body.