If you go to your local supermarket or pharmacy, you are presented with a range of options for Rapid Antigen Tests (RATs). But which one should you choose? How do you know if the test will reliably detect COVID-19? What is the better choice among the many brand options?
Casey says that the team has managed to fluorescently tag a nucleocapsid protein that will enable researchers to benchmark RATs. “When a virus infects you, it gets your body to produce its proteins. The virus essentially hijacks your body’s cell machinery to help the virus continue replicating so that it can infect other people,” he says.
“Essentially, the most abundant protein produced during COVID-19 infection is the nucleocapsid protein. It is one of the most important proteins to understand, and it is what RATs detect the presence of to determine if you are infected with the virus or not.”
But Casey says that RATs often use a flawed system to evaluate their detection capabilities that can lead us to believe they are more sensitive than they really are. “Existing RATs detect the nucleocapsid protein, but researchers evaluate the RATs’ sensitivity using viral cultures, which are an indirect measure of the presence of the nucleocapsid protein. This can also produce highly conflicting data between laboratories,” he says. “So, our research developed a new and more robust tool that can accurately compare the sensitivity of RATs produced by different manufacturers.”
“We really need a tool that allows us to confidently say which RAT is better. This is critical in settings such as aged care and health care where many immunocompromised people are relying on the detection capabilities of these tests,” Casey says.
“If you’re visiting your grandmother in an aged care facility, you want to be sure that you don’t have COVID or the flu. While polymerase chain reaction (PCR) tests remain the gold standard, they are less readily available and can be so sensitive that they can return a positive result from an infection that occurred months ago,” he says. “Obviously that’s why we use RATs more often; they are easy to obtain and help gauge how contagious an individual is likely to be, but we need to be able to trust their results.”