Blood test detects COVID-19 in only 20 minutes

By Juliano Oliveira

Researchers have been able to detect COVID-19 in only 20 minutes through the analyses of blood samples in Australia.

A team of scientists led by BioPRIA, a national research institute, and Monash University, including researchers from the ARC Centre of Excellence in Convergent BioNano Science and Technology, are behind the achievement.

They managed to detect the presence of antibodies raised in response to the SARS-CoV-2 infection. This was possible because positive COVID-19 cases caused an agglutination or a clustering of red blood cells. In only 20 minutes, the researchers were able to retrieve positive or negative readings.

“While the current swab / PCR tests are used to identify people who are currently positive with COVID-19, the agglutination assay can determine whether someone had been recently infected once the infection is resolved – and could potentially be used to detect antibodies raised in response to vaccination to aid clinical trials, explains the scientists.”

This discovery, claim the researchers, may drive medical practitioners to test up to 200 blood samples an hour. Hospitals with high-grade diagnostic machines might increase this number to more than 700 blood samples could be tested hourly – about 16,800 each day.

A patent for the innovation has been filed and researchers are seeking commercial and government support to upscale production.

Dr Corrie, Senior Lecturer in Chemical Engineering at Monash University and Chief Investigator in the CBNS, said this practice has the potential to become upscaled immediately for serological testing.

“Detection of antibodies in patient plasma or serum involves pipetting a mixture of reagent red blood cells (RRBCs) and antibody-containing serum/plasma onto a gel card containing separation media, incubating the card for 5-15 minutes, and using a centrifuge to separate agglutinated cells from free cells,” Dr Corrie said.

“This simple assay, based on commonly used blood typing infrastructure and already manufactured at scale, can be rolled out rapidly across Australia and beyond. This test can be used in any lab that has blood typing infrastructure, which is extremely common across the world.”

Tests

Researchers collect blood samples from patients recently infected with COVID-19, as well as samples from healthy individuals sourced before the pandemic emerged.

Tests on 10 clinical blood samples involved incubating patient plasma or serum with red blood cells previously coated with short peptides representing pieces of the SARS-CoV-2 virus.

“If the patient sample contained antibodies against SARS-CoV-2, these antibodies would bind to peptides and result in aggregation of the red blood cells. Researchers then used gel cards to separate aggregated cells from free cells, in order to see a line of aggregated cells indicating a positive response. In negative samples, no aggregates in the gel cards were observed,” Professor Gil Garnier, Director of BioPRIA, said.

“We found that by producing bioconjugates of anti-D-IgG and peptides from SARS-CoV-2 spike protein, and immobilising these to RRBCs, selective agglutination in gel cards was observed in the plasma collected from patients recently infected with SARS-CoV-2 in comparison to healthy plasma and negative controls.”

“Importantly, negative control reactions involving either SARS-CoV-2-negative samples, or RRBCs and SARS-CoV-2-positive samples without bioconjugates, all revealed no agglutination behaviour.”