Watch: Rapid test measures COVID-19 immunityS. Himmelstein | March 25, 2021
A rapid method has been developed to measure immunity to coronavirus in those who recovered from COVID-19. The inexpensive pinprick assay accurately documents the concentration of coronavirus antibodies in blood in under one hour.
Serological tests detect antibodies — the protein molecules in blood that recognize and neutralize Sars-CoV-2 to prevent infection — and are viewed as a key tool for public health experts to manage the ongoing pandemic because it allows them to measure population immunity. Enzyme-linked immunosorbent assay (ELISA)-based methods are considered the gold standard for determining antibody concentration as a strength of individual immune response, but these approaches require several laboratory steps and six hours to complete, making it unsuitable for rapid diagnostics.
The new faster Serological Assay based on split Tripart Nanoluciferase (SATiN) method is the first COVID-19 serology test that uses highly sensitive protein complementation chemistry in which a light-emitting luciferase protein is reconstituted from separate fragments as test readout.
Some of the luciferase is attached on the viral spike protein, which antibodies bind to in order to neutralize the virus, while other fragments adhere to a bacterial protein that antibodies also interact with. By binding simultaneously to the coronavirus spike protein and the bacterial protein, the antibody helps lock luciferase pieces together into a whole molecule. The result is a flash of light that can be detected and converted into antibody concentration by a plate reader instrument.
The sensitivity of the SATiN method has been demonstrated to be comparable to that of ELISA. The technique developed by researchers from University of Toronto, University of Utah, Public Health Agency of Canada, Sunnybrook Research Institute (Canada), Canadian Blood Services, Mount Sinai Hospital (Canada) and University of Alberta is described in Nature Communications.