Vanillylmandelic acid (VMA) and other catecholamine metabolites such as homovanillic acid (HVA) measurement in urine are used for screening children for catecholamine-secreting tumors such as neuroblastoma and other neural crest tumors and monitoring those who have had treatment for these tumors.
- More than 90% of individuals with neuroblastoma have elevated VMA and/or HVA.
- VMA is not the analyte of choice for diagnosis of pheochromocytoma, which is better detected by testing for metanephrines.
- Treatment with L-dopa can impact test results and should be discontinued 24 hours prior to collection. Bactrim can impact test results and should be noted at time of collection.