Test Details: Catecholamine-secreting tumors are rare neoplasms of chromaffin cells that arise from the adrenal medulla (pheochromocytoma) or paraganglia (paraganglioma). These catecholamines are further boken down into metanephrines. As per some studies measurement of fractionated plasma metanephrines may be the biochemical test of choice, particularly in high-risk patients i.e. those with a familial syndrome or vascular adrenal mass.