Table 1.
Degree of cross-reactivity found with the four antigens assessed by ELISA, and based upon a discrimination between positive versus negative reaction (Youdens J max), yielding thus a relative specificity index with regard to cross-reactive parasitic disease sera.
Figure 1.
Western blot analyses of recSAP2-antigen.
Arrow indicates the 15 Mr size of the revealed recombinant and affinity-purified protein. Western blot findings concerning six different sera from fascioliosis patients with different FhES-ELISA-αhuIgG-AP antibody levels (see text).
Figure 2.
Dot plot showing the distribution of A405 nm values (y-axis) for the four antigens/ELISAs and for the four groups of sera tested (Fh-infection; healthy blood donors; cancer-patients, sera from patients with other parasitoses).
The dotted lines indicate the respective Youndens J max values as shown in Tab. 2 and used as threshold discriminating between positive and negative serology.
Figure 3.
Empirical ROC curves for the four antigens/ELISAs tested.
Figure 4.
Multi-Graph ROC curve showing the empirical value for sensitivity (red), specificity (blue), overall accuracy (green) and Youdens J (violet) as a function of the cutoff value, exemplified in function of the recSAP2-ELISA selected as best operating ELISA among the four assays investigated.
The blue line indicates the cutoff (0.084) at which the overall test performance turned out to be optimal.
Table 2.
Selected cutoff values (*) for which the maximized accuracy criterion (diagnostic sensitivity, diagnostic specificity, overall agreement and combined SE and SP (Youdens J)) was achieved; the table includes also the ROC AUC for the four different Fasciola-ELISAs.