Laboratory measurement of vanillylmandelic acid (VMA), the end product of epinephrine, norepinephrine metabolism, and homovanillic acid (HVA), a terminal metabolite of dopamine, and 5-Hydroxyindolacetic acid (5-HIAA) the end metabolite of serotonin is used to enhance clinical diagnosis and management of catecholamine-secreting neurochromaffin tumors such as neuroblastomas. Neuroblastoma usually emerges in children and accounts for 7–10% of childhood cancer; approximately 90% of these tumors produce catecholamines (CAs). Pheochromocytoma is a rare neuroendocrine tumor arising from the chromaffin cells of the adrenal medulla and characterized by producing excessive amounts of CAs and their metabolites.