Urinary excretion of HMMA and HVA in infants.

Gas chromatography with flame ionisation detection has been used to establish the normal urinary excretion values of homovanillic acid and 4-hydroxy-3-methoxymandelic acid in 808 infants aged 6 months. This study, the essential pre-requisite for population screening for neuroblastoma in babies, reveals a mean homovanillic acid of 10.9 mumol/mmol creatinine and mean 4-hydroxy-3-methoxymandelic of 6.8 mumol/mmol creatinine. The upper 95% confidence interval were 25.5 mumol/mmol creatinine for homovanillic acid and 15.0 mumol/mmol creatinine for 4-hydroxy-3-methoxymandelic. Gas chromatography/mass spectrometry analysis of the 39 samples, (4.8%) with apparent increased excretion of one or both metabolites, revealed that this was, in each case, due to interfering peaks on chromatography.