Human Tuberculosis IgG Antibody ELISA Kit (A314420) employs the indirect enzyme-linked immunoassay technique for the qualitative detection of human Tuberculosis IgG antibody in serum, plasma, and other biological fluids. The antigen recognised by the Tuberculosis IgG Antibody has been pre-coated onto a 96-well microtiter plate. Positive controls, negative controls, and samples are added into the wells and incubated. Antibodies in the sample bind to the pre-coated antigen. Unbound antibody is removed in a wash step. An HRP-conjugated detection antibody is then added and incubated. Unbound HRP-conjugated detection antibody is removed in another wash step. TMB substrate is then added, and color develops. The reaction is terminated by the addition of acidic stop solution and the intensity of the yellow color is measured at O.D. 450nm in a microplate reader. The O.D. 450nm of samples is then compared to that of the positive and negative controls to determine the presence or absence of human Tuberculosis IgG antibody.