The research highlights the wildly varying accuracy of RATs and has prompted calls by the JCU team and others for better quality assurance of the tests.
JCU researchers used a fluorescent protein to develop a new reference standard to check RAT performance.
10 RATs were selected by the team for evaluation, which used a COVID-19 fluorescent protein to determine the lowest detectable amount of COVID-19 protein for each test.
Out of the 10 RATs analysed, only two returned consistently positive readings at the lowest concentration of COVID-19 protein used.
While a recent Canadian study proposed a reference standard for RATs, JCU Associate Professor of Molecular and Cell Biology Patrick Schaeffer said the JCU study was the first of its kind to not only develop a standard but implement it to compare RATs.
“This reference standard has allowed us to make very simple and efficient quality control assessments,” he said.
“At the moment, RAT performance is based on what the manufacturer says but they have never been compared using the same standardised COVID-19 protein.
“Currently, the Therapeutic Goods Administration and World Health Organisation request that manufacturers disclose the analytical sensitivity of their RATs but they are not cross-checked in an independent lab.”
Associate Prof Schaeffer said the study’s results highlighted an urgent need for the TGA and WHO to push for a standard reference material to compare the accuracy of hundreds of different RAT brands.
“We need a reliable reference standard to rank all current and future RAT devices and ensure that their performance is accurately communicated to healthcare providers and the public,” he said.
“We believe our fluorescent nucleocapsid protein is a promising candidate for this task and will ensure that RAT performance is accurately communicated to healthcare providers and the public.
“At the moment, these RATs are assessed using viral cultures, without knowing the actual concentration of the COVID-19 protein.
“It’s like counting the number of mature trees in a forest and using that to determine the number of seeds sown. It depends on factors like soil quality and the viability of the seeds.”
Published in Talanta Open journal, the study was led by Associate Prof Schaeffer and involved JCU PhD candidate Casey Toft, Masters candidate Rebecca A. Bourquin, Dr Alanna Sorenson, Associate Prof Paul Harwood and the Doherty Institute’s Dr Julian Druce.
Media release from James Cook University Australia. Note: Content has been edited for style and length.