A Novel Data Transformation Method for Serologic Diagnosis of Schistosomiasis Japonica

Our study established a new serodiagnostic data transformation method of schistosomiasis japonica such that the cut off value based on normal distribution can be used. Sera collected in 2 different Schistosoma japonica (S j) endemic areas were tested by using a S j specific IgG antibody detection kit. The data were assessed by Stata. Results indicated that before the proposed transformation, the specific antibody level of either population was not normally distributed, but after applying the transformation formula, the level of S j egg positive population was transformed to a normal distribution. As Kato Katz stool examination method may miss some infections, the antibody level of the egg negative population was still not normally distributed after the transformation. Based on the theory of normal distribution, a cutoff value was determined by the antibody level of S j egg positive population. We also proposed a new method to determine the cutoff value for serodiagnosis of S j in a population from S j endemic area.