Comparative analysis of the diagnostic performance of adult, cercarial and egg antigens assessed by ELISA, in the diagnosis of chronic human Schistosoma mansoni infection

Total IgG ELISA was assessed comparing soluble adult worm (SWA), cercarial (SCA), and egg antigens (SEA) using sera of chronic schistosomiasis patients in two different concentrations (1/50 and 1/100). This response showed reactivity against all antigens. Concerning 1/100 serum concentration the SWA gave the best sensitivity (100 %) followed by SCA (86.6 %) and SEA (80 %). The best specificity was obtained from SCA (94.11 %) with an equivalent result from the SWA and SEA (76.47 %). Concerning the 1/50 serum concentration, the SWA gave the best sensitivity (100 %) with an equivalent result from the SCA and SEA (80 %). The best specificity was obtained from SEA (82.35 %) followed by SCA (76.47 %) then SWA (64.7 %). The best AUC value (0.992) was that for SWA indicating its high ability to predict the disease in comparison to (0.914) for SCA and 0.871 for SEA in serum dilution 1/100. The highest AUC value (0.955) was that for SWA in comparison to (0.914) for SEA and (0.88) for SCA in serum dilution 1/50. Comparison between the AUCs from the three mentioned antigens revealed highly significant differences when the data were analyzed by ROC. Each antigen showed a highly statistically significant correlation within its optical density values at both concentrations; 1/100 and 1/50. Comparing the two concentrations in each antigen revealed a non significant correlation obtained from the SWA which signifies a near outcome from both concentrations while the SCA and SEA showed a highly significant difference between the two concentrations. In conclusion, for the diagnosis of chronic schistosomiasis mansoni, total IgG reactivity revealed the best sensitivity by SWA. There was a difference in the type of antigen showing best specificity results between SCA and SEA according to serum concentration used.