Scientists from Monash University, Australia, have developed a new test which can detect antibodies to COVID-19 in as little as 20 minutes.
The test is based on the same process used for blood group typing (that is, detecting if someone is type A, or blood type O etc) and relies on an agglutination assay.
Red blood cells are coated with peptides from COVID-19 and mixed with a patient’s blood sample. If the patient’s blood contains antibodies to COVID-19, these react with the coated red blood cells and clump together (that is, agglutinate). The sample is centrifuged and placed on a gel card which contains a separation media and due to its size, the antibody-red blood cell complex cannot pass through the gel card, and the complex becomes visible as a red line which can be easily visualised on the gel cards.
The assay was tested on ten samples of blood, five of which were positive for COVID-19 and the researchers found that the agglutination reaction was absent from samples without the antibodies.
The authors, who have filed for a patent, called to the test to be further evaluated with a larges sample but commented that because the assay is based on a commonly used laboratory process routinely available across the world, it could be easily scaled up and used to quickly assess for the presence of COVID-19 antibodies.
Alves D et al. Rapid Gel Card Agglutination Assays for Serological Analysis Following SARS-CoV-2 Infection in Humans. ACS sens 2020. https://doi.org/10.1021/acssensors.0c01050.