Effectiveness of two ELISA kits for detecting IgG antibody against severe fever with thrombocytopenia syndrome virus

Abstract

Objective \nTo compare two kinds of commercial ELISA kits for detecting IgG antibody against severe fever with thrombocytopenia syndrome virus (SFTSV) , so as to provide evidences for their application. \n \n \nMethods \nA total of 25 convalescent serum samples from confirmed cases with fever thrombocytopenia and leucopenia syndrome and 385 serum samples from healthy persons were tested by ELISA-1 kit, ELISA-2 kit and microneutralization test (MNT) . Using MNT as the gold standard test, indicators were calculated and evaluated between ELISA-1 kit and ELISA-2 kit. \n \n \nResults \nThe results of 2 ELISA kits for testing IgG antibody of confirmed cases were as good as MNT. However, there were great differences among MNT, ELISA-1 and ELISA-2 for testing IgG antibody of healthy persons with the positive rates of 11.69%, 7.79% and 5.97%, respectively. Compared to MNT, ELISA-1 and ELISA-2 kits revealed the sensitivity of 51.11% and 48.89%, specificity of 97.94% and 99.71%, Youdon’s index of 0.49 and 0.49, positive likelihood ratio of 24.83 and 166.22, negative likelihood ratio of 0.50 and 0.51, consistency value of 0.57 and 0.62. S/CO ratio in false positive samples was 3.02, which was lower than that in mutual positive samples of 17.49. Seven false positive samples had the S/CO ratio of lower than 3.8. \n \n \nConclusions \nELISA-1 and ELISA-2 kits are reliable for detecting IgG antibody of patients with fever thrombocytopenia and leucopenia syndrome. However, the results are not good for detecting IgG antibody of healthy persons due to low consistency and poor diagnostic value. \n \n \nKey words: \nBunyaviridae;\xa0Microneutralization test;\xa0Consistency