In an ImmunoBlot, purified SARS-CoV-2 specific antigens are sprayed as straight lines onto a nitrocellulose membrane and cut into 3mm wide strips. The antigen strip is incubated with patient serum in each trough of an incubation tray. If specific antibodies to SARS-CoV-2 antigens are present, they will bind to the corresponding antigen bands. After washing away unbound antibodies, the bound SARS-CoV-2 specific antibodies are detected with alkaline phosphatase conjugated goat anti human IgM or IgG antibody. A dark purple precipitate will develop on the antigen-antibody complexes. Bands are visualized and scored for intensity relative to the positive and negative controls.
Currently many Lateral flow assays and ELISA tests for detection of SARS- CoV-2 antibodies in human blood samples are available. The Lateral Flow tests are rapid and only require a drop of blood. However, they lack sensitivity and specificity. ELISA tests currently on the market are claiming high specificity, however there is very little information about sensitivity of these tests. Based on the studies to date, the ImmunoBlots prepared using recombinant proteins have superior specificity and sensitivity compared to ELISA and Lateral Flow assays.
Learn more why an ImmunoBlot gives the best answer.
