Use

Homovanillic acid (HVA) and vanillylmandelic acid (VMA) measurements in urine are used for screening children for catecholamine-secreting tumors such as neuroblastoma, pheochromocytoma, and other neural crest tumors; they are also useful for monitoring patients after treatment for these tumors. Additionally, elevated or decreased HVA may indicate disorders of catecholamine metabolism such as monoamine oxidase‑A deficiency or dopamine beta‑hydroxylase deficiency. VMA is not ideal for pheochromocytoma diagnosis, for which metanephrines are preferred. Elevated concentrations of HVA and VMA are suggestive but not diagnostic; further confirmatory testing is required, and a normal result does not exclude disease.