A trial for reducing false-positives in screening for neuroblastoma by baby food developed for the screening

为明确神经母细胞瘤筛查假阳性的原因，我们进行了一项实验和流行病学研究，目的是首先通过测定滤纸收集的尿液中的VMA来明确筛查假阳性的原因，其次是通过开发筛查婴儿食品来减少假阳性，第三是为6个月大的婴儿的母亲制定新的筛查指南。首先，在体内研究尿检和禁食之间的剂量效应和时间关系，在体外，婴儿和哺乳的母亲服用禁食会导致假阳性。其次，一项旨在通过建议母亲给婴儿提供筛查食品来减少假阳性的人口试验。第三，通过问卷调查，对筛查前食品中阴性和假阳性婴儿的差异进行了调查。婴儿口服橙汁和香蕉的假阳性率很高。假阳性持续时间为服药后1~数小时，20小时后均未见阳性结果。未观察到橙汁摄入量的明显量效关系。橙汁中导致假阳性的物质通过母乳传递给婴儿，这一过程持续了20多个小时。人口试验产生了以下结果。有指导和无指导的婴儿假阳性率无差异。在阴性组和假阳性组中，服用其他食物的婴儿比例分别为37%和47%，但差异无统计学意义。需要进一步分析两组之间摄入的食物类型的差异。

An experimental and an epidemiologic studies were conducted with the aims of firstly clarifying the cause of false-positives in screening for neuroblastoma by measurement of urine VMA collected with filter paper, secondly reducing falsepositives by developing baby food for the screening, and thirdly establishing new guidance to mothers of 6-month-old babies, candidates for the screening.The research consisted of three phases. Firstly, investigation of the doseeffect and time relationsip in vivo between the urine test and intake of contraindicated food, known to cause false-positives in vitro, when taken by babies and when taken by mothers who breast feed. Secondly, a population trial to reduce false-positives by advising mothers to give baby food developed for the screening. Thirdly, investigation through a questionnair survey of the difference between negative and false-positive babies in foodstuffs taken before the screening.The result of the experimental study revealed the following. Orange juice and banana taken orally by infants induced a very high false-positive rate. The falsepositive results lasted from one to several hours after intake and after 20 hours no positive result was found. No apparent dose-effect relationship was observed for the intake of orange juice. Substances in orange juice causing false-positives passed to infants through breast milk and this lasted for more than 20 hours.The population trial yielded the following results. No difference was observed in the false-positive rate between those infants under the guidance and those without the guidance. Proportion of infants who took other food than was indicated was 37% in the negative group and 47% in the false-positive group, but the difference was not statistically significant. Further analysis of the difference in the types of food taken between the two groups is needed.