International study highlights best RATs

The new joint study by JCU and National Research Council Canada analysed 16 RATs approved by Australia’s Therapeutic Goods Administration (TGA) and 10 by Health Canada, using a JCU-developed COVID-19 protein and its Canadian counterpart as reference materials.

Out of the total 26 RATs compared, only six were found to be effective at detecting the lowest concentration of the COVID-19 reference proteins in the dilution series used for benchmarking.

One of the Canadian RATs, which had its approval revoked by the TGA in 2022, failed to detect the COVID-19 protein entirely at any level of concentration used in the dilution series.

It follows a world-first study last year by JCU researchers which found significant differences in the analytical performance of TGA-approved RATs.

Study co-author and JCU Associate Professor of Molecular and Cell Biology Patrick Schaeffer said the study findings underscored an absolute need for independent evaluation of RATs both in Australia and overseas.

“What was most shocking in this study was not only that we have some poorly-performing RATs but that there seems to be no easy way to get them off the shelves,” he said.

“There’s no point in having these underperforming RATs sold to people, especially those which can only detect COVID-19 in people who are at the peak of their infection.”

Associate Prof Schaeffer said the study had also shown the two different types of proteins used by each lab in Australia and Canada to test the RATs were superior to using viral cultures as a testing standard.

“We used two differently engineered nucleocapsid proteins produced in two different labs on different sides of the planet and we got exactly the same results,” he said.

Associate Prof Schaeffer said he now wanted to broaden his study to analyse RATs capable of detecting different strains of Influenza A and B viruses.

“There were actually two RATs in this latest study which are designed to detect Influenza A and B as well as COVID-19, but neither of them detected influenza proteins particularly well,” he said.

“We’d like to look at how well influenza RATs can detect subtypes like H3N2, H5N1 ‘bird flu’ and H1N1, otherwise known as swine flu.

“We have all of those proteins produced and the next stage is to start a review of these particular RATs.”

Published in Talanta, the study was led by JCU PhD candidate Casey Toft, National Research Council Canada’s Bradley Stocks and Associate Prof Schaeffer.