A longitudinal study of comparison of the Kato-Katz technique and indirect hemagglutination assay (IHA) for the detection of schistosomiasis japonica in China, 2001-2006

From 2001 to 2006, about one-third of the residents aged 5-65 years were selected as the subjects in a schistosome-endemic village located in Jiangxi Province, China. Every 1 year, all participants were analyzed by the Kato-Katz parasitologic examination and indirect hemagglutination assay (IHA). Statistical analysis of the results showed the k indices ranged from 0.250 to 0.347 between the two methods. Assuming the Kato-Katz results as the gold standard reference, the specificity of the IHA was from 60% to 77%, the positive predictive value of this method was from 19% to 30%, and its sensitivity and negative predictive value were more than 97%. The IHA method is unsuitable for individual screening in endemic community with relatively high prevalence (e.g. with >10% or more prevalence). A search for a better diagnostic test that can be applied in field situations in China is essential and should be given high priority.