acid.Vanillyl mandelic acid (VMA) is an end-stage metabolite of the catecholamines epinephrine and norepinephrine. It is produced via intermediary metabolites.Urinary VMA is elevated in patients with tumors that secrete catecholamines. These urinalysis tests are used to diagnose an adrenal gland tumor called pheochromocytoma, a tumor of catecholamine-secreting chromaffin cells. These tests may also be used to diagnose neuroblastomas, and to monitor treatment of these conditions.">