RESUMO
At present, urinary vanillylmandelic acid (VMA) and/or homovanillic acid (HVA), metabolites of catecholamines, are the most sensitive diagnostic markers of neuroblastoma. They can be measured by the high-performance liquid chromatographic method, which has been used to screen for neuroblastoma in infants in Japan. From 6486 urine samples of 18-month-old children, 103 samples showed high HVA levels over the cutoff point for neuroblastoma, and most of them also showed markedly high levels of 5-hydroxyindoleacetic acid (5-HIAA), a metabolite of serotonin. One of the causes of high HVA excretion might be due to the ingestion of banana, common weaning food in early childhood. Our study showed that it is better to restrict banana ingestion within 24 hours before taking a urine sample for diagnosis of neuroblastoma and that 5-HIAA is a good marker of a pseudopositive result due to banana ingestion.