SARS-CoV-2 S1RBD IgG ELISA Kit is a highly sensitive and specific immunoassay developed by ImmunoDiagnostics for the precision detection and quantitative measurement of IgG class antibodies against the S1RBD of SARS-CoV-2 virus in human blood samples.

This product is intended for used by professional persons only.

This product is intended for research use only.

In December 2019, a novel coronavirus, now officially named as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been identified in Wuhan China, which caused the outbreak of a coronavirus-associated acute respiratory disease called coronavirus disease 19 (COVID-19). Signs and symptoms of COVID-19 may occur 2 to 14 days after infection, which include fever, cough, shortness of breath or difficulties in breathing, pain in the muscle and tiredness. In severe cases, the infection can further lead to pneumonia, severe acute respiratory syndrome (SARS), kidney failure and death.

The spike protein (S) is an envelope-anchored protein that mediates the recognition and binding of SARS-CoV-2 to host cells. S can be further cleaved by the host protease into two subunits called S1 and S2. S1 polypeptide contain a receptor binding domain (S1RBD) crucial for the specific recognition and interaction with the human receptor ACE2, which is the first and the most essential step for the virus infection.

ImmunoDiagnostics SARS-CoV-2 S1RBD IgG ELISA kit is a two-step incubation immunoassay kit. Recombinant spike protein S1 receptor-binding domain (S1RBD) of SARS-CoV-2 pre-coated onto the polystyrene microwell strips can specifically recognize anti-S1RBD antibodies in human serum or plasma specimen. After a 1-hour incubation, anti-S1RBD antibodies are captured by immobilized S1RBD protein while the unbound components are washed away. Afterwards, a detection solution containing HRP-conjugated anti-human IgG is added for another 1-hour incubation, wherein HRP-conjugated anti-human IgG binds to the IgG class antibodies previously bound to S1RBD protein on the plate. After removal of nonspecific bindings, a HRP substrate solution containing 3,3′,5,5′-Tetramethylbenzidine (TMB) is added, resulting in the formation of a blue color. Color reaction is stopped by 2M H2SO4, transforming the blue color to yellow signals, which is quantified by an absorbance microplate reader at 450nm. The color intensity is proportional to the amount of anti-S1RBP antibodies captured inside the wells. The unknown sample concentration can be interpolated from a standard curve generated by the humanized anti-S1RBD monoclonal antibody (mAb).

Handle serum or plasma sample in accordance with National Committee for Clinical Laboratory Standards guidelines for preventing transmission of blood-borne infection.

• Do not use grossly hemolyzed or lipemic samples.
• Human Serum: Use a blood separator tube and allow sample to clot for 30 minutes, then centrifuge for 10 minutes at 1000g. When the human serum is tested, it should be diluted 100-fold at least.
• Human plasma: Treat blood with anticoagulant such as citrate, EDTA or heparin. Centrifuge for 10 minutes at 1000g within 30 minutes for plasma collection. When the human plasma is tested, it should be diluted 100-fold at least.
• Samples cannot be tested immediately should be aliquoted and must be stored frozen below - 20°C. Avoid repeated freeze-thaw cycles.
• Perform preliminary experiment to determine the optimum detection sample dilution.

• The kit should be stored at 2-8°C, and all reagents should be equilibrated to room temperature before use. Immediately after use remaining reagents should be returned to cold storage (2- 8°C).
• Expiry of the kit and reagents is stand on labels.
• Once opened, the strips may be stored at 2-8°C for up to one month.