Key Points
- Combination RATs can identify COVID-19, influenza A and influenza B.
- Seven different combination tests have been approved for sale in Australia.
- Immunologists say the tests will be most useful during the winter flu season.
Combination rapid antigen tests (RATs), which allow users to test for influenza A and B as well as , have recently started to appear on pharmacy shelves.
While the nation's medicines watchdog, the Therapeutic Goods Administration (TGA), gave them the green light in September 2022, five of the seven brands on sale in Australia have only been approved since the start of 2023.
The combination tests work in the same way as traditional RATs, with the user placing their test sample in a well on the kit and waiting a short length of time for a control line to show up.
Separate lines indicate the result for influenza A, influenza B, and COVID-19.
How useful are combination RATs?
Influenza and COVID-19 rarely occur together, according to Professor Catherine Bennett, the chair of epidemiology at Deakin University.
Professor Bennett said the ability to test for influenza and COVID-19 at the same time would be useful ahead of winter when takes hold.
She said while people who tested positive for the viruses should generally rest and keep a distance from others, understanding whether they had COVID-19 or influenza could help them better manage their illness.
"If you've actually got symptoms, and you had a combined test, and it says you've got influenza, then you don't have to worry about doing to get that PCR," Ms Bennett said.
"And you do have to distinguish between influenza to know whether a person is eligible for the COVID antivirals (treatment)."
Home test kits used to identify influenza varieties (pictured above) and combination COVID-19 and influenza RATs have been available in other countries for some time. Source: Getty / Future Publishing
Professor Bennett said while people were not likely to be testing for COVID-19 as often they were earlier in the pandemic, she said knowing whether the illness was caused by COVID-19 or influenza was important.
"Knowing it's COVID is important because that can actually change your decision about when you're ready for a , the decision is based on six months from your last infection, or booster," Ms Bennett said.
The ability for people to test at home had the potential to alleviate some of the demand on GPs where people would otherwise be "sitting in the waiting room and spreading it to others", said Cassandra Berry, a professor of immunology at Murdoch University.
According to the TGA, as with traditional RATs, combination tests are not as accurate as PCR tests which are carried out in laboratories.
The TGA states results are more reliable when used by a person with symptoms of COVID-19 and influenza, and are generally best performed within the first seven days from when symptoms first appear for COVID-19 and within the first four days from when symptoms first appear for influenza.
Professor Berry said respiratory syncytial virus (RSV) was another common virus, and it would be useful if RATs could test for this in the future.
'COVID-19 testing will always have a purpose'
Professor Berry said while some people may see the availability of the tests in Australia coming too late in the pandemic she said medical innovations still had a role to play.
"I know everyone wants the narrative to go away, all the restrictions are being relaxed, and we're almost living normally now, but it just depends on what's happening around the globe," she said. "If we do get another variant then this test will be even more useful. I don't think we can ever say it's too late down the track. I think it'll always have a purpose."
All of the COVID-19 rapid antigen self-tests and combination self-tests that are approved for supply in Australia are listed on the
