Development and evaluation of a competitive enzyme-linked immunosorbent assay using a monoclonal antibody for diagnosis of severe fever with thrombocytopenia syndrome virus in bovine sera

Lee, Hyojin; Kim, Eun-Ju; Song, Jae-Young; Choi, Jeong Soo; Lee, Ji Youn; Cho, In-Soo; Shin, Yeun-Kyung

Because official standard methods for the antibody detection of SFTSV have not been determined, the cut-off criteria determination for IFA requires further optimization. Therefore, ROC curve was employed to determine the sensitivity and specificity and define the optimal cut-off value for IFA. The ROC curves of four different IFA cut-off values were compared, and the results showed that a 1/80 dilution of the sample strongly supports the result of cELISA. For this dilution, the area under the curve (AUC) was 0.91. While a 1/128 dilution rate as an IFA cut-off point maximizes the specificity and sensitivity compared with other dilution rates, this condition is too strict to detect positive samples above the strict threshold in cELISA. The other IFA cut-off conditions (1/16 and 1/64) were also excluded because they showed moderate AUC values (Fig. 7) .