Neuroblastomas (NB) are catecholamine producing tumors and diagnosis is possible by analyzing for metabolic by-products of catecholamine in urine.

In this report vanillylmandelic acid (VMA), homovanillic acid (HVA) and creatinine were measured simultaneously by reversed phase HPLC and pre-processing was remarkably improved by HPLC autosampling with a micro-plate. A UV detector was used for creatinine and a coulometric detector (ECD) for VMA and HVA.