Scientists from Singapore and the USA have created a rapid test for antibodies to new variants of SARS-CoV-2 
Researchers from Singapore and the USA have developed a rapid test to determine the level in the blood of antibodies that neutralize the new variants of the SARS-CoV-2 coronavirus. It only requires a drop of blood from a finger, and the process itself takes only ten minutes. A description of the development and its action is described by scientists in the journal Communications Medicine and in a preprint on medRxiv.
Currently, the level of neutralizing antibodies to SARS-CoV-2 in human blood is still determined in specialized centers using tests for the neutralization reaction viruses that require a high level of biosecurity and take two to four days. Researchers at Nanyang Technological University, the National University of Singapore and the Massachusetts Institute of Technology have created a new rapid test to neutralize the virus. It is a paper strip that is impregnated with a solution with the receptor-binding domains of the S-protein of the coronavirus. A sample of the patient's blood is applied to them and a luminous dye, which includes molecules of the ACE2 receptor, a gateway to the cell for SARS-CoV-2.
Antibodies in the blood will prevent the S-protein from joining with fragments of the coronavirus envelopes – and less tinted viral particles will settle on the strip. The researchers tested the accuracy of their test on blood samples from several dozen patients vaccinated with Pfizer against the Wuhan, alpha, beta, gamma and delta variants of the coronavirus. The accuracy of the test was 93 percent – which is higher than that of laboratory tests. In addition, testing has confirmed a significant decrease in antibody titer in the blood of people three months after vaccination.