©2019 by ImmunoDiagnostics Limited.


SKU: 41A223



    Since December 2019, outbreak of SARS-CoV-2 infection has become a major epidemic threat in China and brought back the attention of pathogenic coronavirus to the spotlight. Spike protein is an envelopeanchored protein that mediates the recognition and binding of SARS-CoV-2 to host cells. S1 can be further cleaved by the host protease into two subunits called S1 and S2, wherein the S1 polypeptide contain a receptor binding domain (RBD) crucial for the specific recognition and interaction with human receptor ACE2, which is the first and the most essential step for the virus infection. Human anti-SARS-CoV-2 spike protein S1 receptor-binding domain (S1RBD) IgG ELISA kit is a highly sensitive and specific ELISA kit developed by ImmunoDiagnostics for the precision detection and quantitative measurement of titres of anti-S1RBD IgG class antibodies in human serum.

    This product is intended for use by professional persons only.

    This product is intended for research use only.



    Recombinant spike protein S1 receptor-binding domain (S1RBD) of COVID-19 (Cat No. 41A221) coated onto the plate wells can specifically recognize anti-S1RBD antibodies in human sera. After a 1 hour incubation, anti-S1RBD antibodies are captured by immobilized S1RBD protein while the unbound components were discarded and washed away. Afterwards, HRP-conjugated anti-human IgG is added for another 1 hour incubation, wherein the anti-human IgG detects IgG class antibodies previously bound to S1RBD protein on the plate. After removal of nonspecific bindings, bound antihuman IgG is revealed by the addition of substrate solution containing 3,3′,5,5′-Tetramethylbenzidine (TMB), resulting in the formation of a blue color. Color reaction will be further stopped by 2M H2SO4, transforming the blue color to yellow signals. The absorbance of yellow reaction mixture is measured by plate reader at 450nm. The higher the reading is, the higher concentration of anti-S1RBD IgGs.

  • Storage and Preparation of Test Serum Samples

    • Test samples are suggested to be assayed immediately after separation of serum, or preferably stored at -20°C or below in aliquots. Duplicate test is recommended.
    • When required, vortex test serum samples at room to ensure homogeneity. Then centrifuge samples at 10,000 to 15,000 rpm for 5 minutes prior to assay to remove particulates. Please do not omit this centrifugation step if samples are cloudy and containing particles.

    The kit should be stored at 2-8°C upon receipt, and all reagents should be equilibrated to room temperature before use. Remove any unused antigen-coated strips from the microplate, return them to the foil pouch and re-seal.  Once opened, the strips may be stored at 2-8°C for up to one month.