Finland develops rapid coronavirus test

An antigen-based detection technique developed by University of Helsinki researchers could be used to analyse as many as 500 samples per hour, said the university in a press release on Wednesday, quoting a study findings.

The results come in roughly 10 minutes later and the formation of any complexes demonstrates, to a high degree of certainty, an infection caused by SARS-CoV-2 in the test subject.

According to the recently completed study, the rapid test was able to diagnose a viral infection almost as accurately as PCR tests, which are known for their sensitivity.

The new rapid test format can also be used to rapidly diagnose other respiratory infections.

The researchers developed a new rapid assay principle for viral antigen detection, applying it to diagnosing SARS-CoV-2 infections.

The test is based on a phenomenon known as time-resolved Förster resonance energy transfer (TR-FRET), where energy travels between two light-sensitive molecules when they are close enough to each other.

TR-FRET makes it possible to measure viral particles or the body’s own proteins by using what are known as ‘mix and read’-type tests on complex biological samples, such as serum or even blood. In fact, the researchers have previously applied the procedure in the rapid detection of antibodies.

As per the function of the test, a nasopharyngeal swab taken from the test subject is mixed in a test solution which contains antibodies that recognise the SARS-CoV-2 nucleoprotein or spike protein.

The antibodies marked with fluorescent labels bind with SARS-CoV-2 particles, forming molecular assemblies, or complexes, whose existence can be confirmed/detected by using a TR-FRET assay.

“We demonstrated in our study that a technique based on the TR-FRET phenomenon can be used to diagnose SARS-CoV-2 infections in clinical specimens”, said Jussi Hepojoki, docent of virology and an Academy of Finland research fellow at the University of Helsinki.

In addition to the novel coronavirus, the assay principle can be utilised to detect other respiratory infections or basically any molecule: the only thing needed is an antibody capable of identifying the target molecule.