Hu SARS-CoV-2 NP IgG Antibody ELISA Kit

From STEMCELL Technologies, this Human SARS-CoV-2 Nucleoprotein IgG Antibody ELISA Kit is designed for the qualitative detection of human SARS-CoV-2 nucleoprotein (NP) IgG antibody in biological fluids such as serum and plasma. The assay is based on the indirect ELISA method, in which samples are added to ELISA strip plates pre-coated with human novel coronavirus nucleoprotein. Antibodies present in the sample specific for the coronavirus nucleoprotein will bind to the pre-coated antigen, and the captured antibodies are detected by addition of an anti-human IgG-conjugated horseradish peroxidase (HRP). Addition of the chromogenic enzyme substrate 3,3',5,5' tetramethylbenzidine (TMB) results in a colored product with an intensity directly proportional to the concentration of human SARS-CoV-2 NP IgG antibody in the sample.

Serum and plasma samples are diluted 1 in 100 in ELISA Diluent prior to assay, and the plate is incubated at 37°C for 30 minutes following sample and detection antibody addition. TMB Substrate is incubated at 37°C in the dark for 20 minutes, after which Stop Solution is added and absorbance is measured at 450 nm, with an optional correction wavelength of 540 nm or 570 nm. Sample positivity is determined by comparing the optical density of the sample well with the negative control well: a sample is considered negative when the OD is < 2.1X the OD of the negative control, and positive when the OD is ≥ 2.1X the OD of the negative control.

Both the intra-assay and inter-assay precision of this assay are < 15% (CV). The assay has high specificity for the detection of human SARS-CoV-2 nucleoprotein IgG antibody, with no significant cross-reactivity or interference known to occur between human SARS-CoV-2 N IgG antibody and analogues. All components are stable until the expiry date on the label when stored at 2 - 8°C.