Rapid antigen testing guidelines published

New guidance for businesses considering rapid antigen testing has been released by the Therapeutic Goods Administration (TGA).
 
The tests are cheaper and offer faster results than the polymerase chain reaction (PCR) testing.
 
Those PCR tests, widely described as the ‘gold standard’ for COVID-19, have been a pillar of the test and trace policy that has, until recently, successfully limited case numbers in Australia.
 
However, while they are more accurate than the rapid antigen testing, they usually need to be sent to a laboratory and take longer for the results to be returned.
 
With an increasing number of COVID-19 cases in the community, rapid antigen testing is now increasingly seen as a tool to monitor and control the virus’ spread, particularly in workplaces.
 
The TGA guidance is likely a forerunner for wider workplace testing, although it does not include specific advice for general practice.
 
For Professor Mark Morgan, Chair of RACGP Expert Committee – Quality Care (REC–QC), the use of rapid antigen testing is only likely to increase. However, he highlighted a number of queries to be addressed before their role for GPs is clear.
 
‘I think they are going to be part of the model for living with COVID for the future,’ Professor Morgan told newsGP.
 
‘There comes a time if COVID-19 is accepted as something that is out there in the community, then we need to think of ways to live with it and reduce the harm of it.
 
‘[The tests] might be part of the model of reducing that risk and reducing super-spreader events.’
 
However, Professor Morgan also warned the tests have their limitations.  
 
‘They are not a panacea, that’s for sure,’ he said.
 
One of the most high-profile concerns surrounding rapid antigen testing is their accuracy. They tend to only test positive just before the onset of symptoms and for a week once symptoms have set in. They are known to be more likely to return a false negative or false positive compared to a PCR test.
 
Infectious diseases physician and microbiologist Associate Professor Paul Griffin of the University of Queensland says that while he thinks the tests should be used more widely, he has concerns about the impact of an incorrect result.
 
‘A false negative in someone who was potentially infectious, if they were not mindful of the limitations of this type of testing, could have very significant consequences in terms of contributing to the onward transmission of the virus,’ he said.
 
Rapid antigen testing and GPs
Under the TGA guidelines, the use of the testing kits – which are made by manufacturers in Australia – is illegal at home, with a testing scheme currently requiring oversight by a health practitioner.
 
While Federal Health Minister Greg Hunt is reportedly considering allowing the rapid antigen tests to be used at home, Professor Morgan said GPs could potentially be involved in overseeing testing schemes in workplaces.
 
Rapid antigen tests are already in wide use overseas, including in the United Kingdom and the United States, and last month the Department of Health made them available for aged care homes in New South Wales hotspot areas.

Professor Adrian Esterman, the Chair of Biostatistics at the University of South Australia, said the tests will also likely be of use in places where lots of people pass through.
 
‘Rapid antigen tests are ideal for airports, transport hubs, industry settings, schools, etc. Their slightly poorer accuracy is less important in these situations,’ he said.
 
Professor Morgan also highlighted outstanding queries about how the tests would work – saying that the current guidelines are geared towards large workplaces with many employees rather than general practices.
 
He points out the wide variety of test manufacturers now approved by the TGA and queried how they could all provide training and evaluate efficacy.
 
‘That’s just not practical when there is 132 of them,’ he said. ‘That needs to be part of the thinking, how is this going to play out at the coalface of systems such as general practice and [other] primary care services.’
 
Professor Deborah Williamson, a microbiologist at the Doherty Institute who helped administer a pilot scheme for rapid antigen testing at three Melbourne hospitals last year, has also said the efficacy of the tests needs be measured carefully.
 
‘It will be important when they are rolled out, for the use of them to be evaluated properly,’ Professor Williamson told the Doherty Institute’s Infection and Immunity podcast last month.
 
‘Every time they are rolled out in a different scenario or a different setting, [we should] try and really apply an implementation science angle to this and learn lessons from each of the different rollouts.
 
‘Hopefully there will be a lot of sharing of information.’



Professor Morgan believes rapid antigen testing may also be useful to help general practices stay open as the virus becomes more commonplace.
 
‘There needs to be a change of approach to general practices,’ he said.
 
‘We’re the frontline workers, we have a lot of contact with the general public, both symptomatic and not symptomatic.
 
‘To close down an essential health service every time someone has COVID-19 might make sense when there is a tiny amount of it in the community, but as soon as there is more than a tiny amount, it doesn’t make sense.’
 
If tests can gauge whether someone is likely to pass the infection on, he believes their use would be justified.
 
‘You can imagine the tests being quite useful if they were able to determine that,’ he said.
 
The issue of who would pay for the tests is also a detail that is as yet unresolved.
 
‘These tests are not free,’ Professor Morgan said.
 
‘General practices have to operate as small businesses and although we provide an absolutely essential part of the healthcare for the country, we can’t do that at the expense of business sustainability.’
 
He believes any planning for the use of rapid antigen testing in general practice needs to incorporate a consideration of the time required to set up the right systems as well as cover the expense of the tests.
 
‘The cost of providing that new layer of healthcare needs to be taken into account,’ he said. ‘There is lot to be worked through.’
 
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