Fig. 5From: A neutralizing monoclonal antibody-based competitive ELISA for classical swine fever C-strain post–vaccination monitoringStandardization of the cut-off value of 6B211 based cELISA. a C-strain VNT negative serum samples (n = 445); b C-strain VNT positive serum samples (n = 70). The dotted line represents cut-off value of 6.19% inhibition when using the mean PI of negative sera plus three SD as the thresholdBack to article page