FIG. 2.

TG-ROC analysis of iELISA results for detection of IgG antibodies to Brucella abortus S-LPS-enriched fraction using anti-bovine IgG-HRPO or protein A-HRPO as conjugates. Sensitivity (Se) and specificity (Sp) of iELISAs were determined for each RI value in order to discriminate positive serum samples from recently vaccinated serum samples (GI × GII) (A and D), from tardily vaccinated serum samples (GI × GIII) (B and E), or from negative serum samples (GI × GIV) (C and F). The intersection point of the curves (Se and Sp) indicates the RI value at which equivalent maximum sensitivity and specificity can be achieved.