Figure 2.

Comparison of patient sera that tested positive in the anti-double-stranded DNA nucleosome-complexed enzyme-linked immunosorbent assay (Anti-dsDNA-NcX ELISA) and other investigated test systems shown in Venn diagrams. (A) Absolute numbers of patient sera that tested positive in the Anti-dsDNA-NcX ELISA (dsDNA-NcX), the anti-dsDNA ELISA (dsDNA) and the anti-dsDNA nucleosome ELISA (Nuc) and their combined intersections are shown. (B) The same analysis as in Figure 2A is shown, including different detection techniques using Anti-dsDNA-NcX ELISA, Farr assay (radioimmunoassay) and Crithidia luciliae immunofluorescence (CLIF) assay is presented. Cutoffs for all positive test results were read out of receiver operating characteristic curve analysis at a specificity of 98.15% because this specificity was calculated for the CLIF assay.