日本血吸虫抗体检测试剂盒（IHA法）现场筛查效果的评估

目的评估日本血吸虫抗体检测试剂盒（IHA法）的现场筛查效果。方法选择安徽省长江流域3个血吸虫病流行区7个流行村的6～65岁居民为查病对象，在用改良加藤厚涂片法（Kato—Katz法，一粪三检）合并尼龙绢集卯孵化法进行病原学检测的同时，采用日本血吸虫抗体检测试剂盒（IHA法）进行血清特异抗体检测，评估其现场筛查效果，并与胶体染料试纸条法（DDIA）和酶联免疫吸附试验（ELISA）检测结果比较。结果7个村共有3004人同时接受2种病原学检测和3种血清免疫学检测，IHA、DDIA和ELISA法的阳性率分别为40．81％、59．79％和59．25％，与病原学检测阳性率2．46％比较差异有统计学意义（P〈0．005）。以病原学检测为金标准，IHA法的特异度、约登指数、一致率和阳性预测值高于DDIA和ELISA法，分别为60．48％、52．37％、61．25％和5．55％；敏感度和阴性预测值分别为91．89％和99．66％，均介于DDIA法和ELISA法之间。IHA法与DDIA和ELISA法的一致率分别为65．25％和69．91％，IHA检测结果与DDIA和ELISA比较差异均有统计学意义（P〈0．05）；病原学检测阳性者中，IHA法与DDIA和EI，ISA法的一致率均为90．54％，IHA检测结果与DDIA和ELISA比较差异无统计学意义（P〉0．05）。结论日本血吸虫抗体检测试剂盒（IHA法）适用于血吸虫病流行区人群筛查，但需进一步提高该试剂盒的特异度，最大限度地排除阳性者中已经治愈的中远期感染者。

Effectiveness of an indirect hemagglutination assay kit at diagnosing schistosomiasis in the field

Objective To evaluate the effectiveness of an indirect hemagglutination assay kit at diagnosing schistosomia sis in the field. Methods Stool specimens from residents 6-65 years of age in 7 villages with schistosomiasis om breaks in 3 regions of Anhui Province were examined using the Kato Katz technique （3 thick smears） and the miracidium hatch ing test （ova are collected in a nylon bag, suspended in water, and allowed to hatch）. An indirect hemagglutination assay （IHA） was carried out in parallel and then compared to a dipstick dye immunoassay （DDIA） and enzyme-linked immu nosorbent assay （ELISA）. Results Two types of stool examinations and 3 methods of immunological diagnosis were used to test samples from 3 004 individuals. Results of the IHA were positive at a rate of 40.81%, DDIA results were positive at a rate of 59.79%, and ELISA results were positive at a rate of 59. 25%. These rates were all higher than the rate indicated by a stool examination （2.46 %）（P〈0.05）. With a stool examination serving as a gold standard. the IHA yielded the best results with a specificity of 60.48%, a Youden＇s index of 52.37%, a rate of concordance of 61.25%, and a positive predictive value of 5.55%. The IHA had a sensitivity of 91.89% and negative predictive value of 99.66%, and both of these numbers fell between the sensitivity and negative predictive value of DDIA and ELISA. The IHA agreed with DDIA at a rate of 65.25% and with ELISA at a rate of 69.91%; differences in the rate of concordance were statisti cally significant （P〈0.05）. For stool specimens that tested positive, the IHA agreed with DDIA at a rate of 90.5d % and with ELISA at a rate of 90.54%. There were no significant differences in the rate of concordance（P〉0.05）. Conclusion An indirect hemagglutination assay kit to diagnose schistosomiasis can be used to screen individuals in areas where schistosomiasis is prevalent, but its specificity needs to be improved further.