[Application of F-ELISA for immunodiagnosis of schistosomiasis japonica].

OBJECTIVE

To optimize the experimental conditions of fast enzyme-linked immunosorbent assay (F-ELISA) and evaluate its performance for immunodiagnosis of schistosomiasis japonica.

METHODS

HRP-SPA was used at different concentrations in the assay to determine the best HRP-SPA concentration by comparing the detection accuracy. The working conditions of F-ELISA were optimized by examining the ratio of absorbance values of positive and negative controls with different incubation time of serum samples and HRP-SPA. To evaluate the performance of F-ELISA in diagnosis of schistosomiasis, the detection accuracy of F-ELISA was compared with routine ELISA and dipstick dye immunoassay (DDIA) by testing serum samples from both healthy subjects and those clinically diagnosed with schistosomiasis and clonorchiasis in parallel.

RESULTS

In F-ELISA, the best working concentration of HRP-SPA was 1:2 000 while the optimized incubation condition for serum samples and HRP-SPA was 60 min at 37 degrees C. Using F-ELISA, we identified 93.8% to be schistosomiasis positive among chronic schistosomiasis subjects, 4% within the clonorchiasis group, and a false positive rate of 1.5% in healthy individuals. This diagnostic accuracy for F-ELISA was similar to routine ELISA and DDIA.

CONCLUSIONS

F-ELISA combines the 2-steps of routine ELISA into a single step making the assay process faster and simpler without sacrificing the diagnostic accuracy. With further investigations, F-ELISA as an easy and practical method is promising to be applied for schistosomiasis diagnosis in the field.