ABSTRACT
Objective To explore the cut?off value of the indirect haemagglutination test(IHA)method for schistosomiasis japonica diagnosis in different endemic areas. Methods Totally 55 nature villages of the lake?type endemic counties,Yugan and Xinzi,in Poyang Lake Region of Jiangxi Province were chosen as the study fields,and all the villagers over 5 years old were parallelly examined by Kato?Katz method+miracidial hatching test and IHA method. The detection data were analyzed by the correlation analysis,and the threshold values of the IHA method in different endemic areas were decided by the receiver operat?ing characteristic(ROC)curve. Results The positive rate of stool examinations of the villagers was correlated with the distribu?tion trend of the antibody level of whole population(r=0.588,P0.05). The antibody level of stool?negative population during the period of 2008 to 2011 detect?ed by IHA method dropped year by year,and the annual difference was statistically significant(F=3.650,P0.05). When the positive rates were5%,the specificity of diagnosis could be improved when 1∶80,1∶20 and 1∶10 were used as the cut?off val? ues of IHA correspondingly. Conclusion The different threshold values for diagnosis of schistosomiasis japonica should be con?sidered while using IHA method to screen out patients in different endemic areas.