Canberrans have been told rapid Covid antigen testing is not a silver bullet to easing a bottleneck in the ACT.
Like the more common PCR tests, rapid antigen tests relied on swabs from the throat and nose, but can produce results within 15 minutes.
Attention has turned to easing the pressure on the ACT testing regime, struggling under the strain of demand since its lockdown was announced on Thursday.
But ACT Australian Medical Association President Walter Abhayaratna insisted PCR remained the "gold standard" and cast serious doubt on the accuracy of rapid testing.
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He said antigen tests were a useful supplement during large outbreaks, but would prove counterproductive while case numbers remained low.
"At the current prevalence rates of positive Covid cases [in the ACT], the rapid antigen tests would add to the confusion because of the high rates of false positives and false negatives," he told The Canberra Times.
Dr Abhayaratna warned 70-90 per cent of positive tests produced by an antigen tests were false.
"And one-in-two, or one-in three, cases that actually are COVID-19 would be missed by the rapid antigen test," he said.
Those figures were based on a Covid prevalence rate of 0.5 per cent, higher than Canberra's current rate, he said.
The Therapeutic Goods Administration has approved 24 types of antigen testing, which can only be supplied to accredited health care professionals in Australia.
Aged care provide Whiddon trialled antigen tests in July, while a Commonwealth pilot in western Sydney aged care centres began on Monday.
"The PCR test would pick [Covid] up earlier. But as long as the rapid antigen tests are reasonably good, then if you are seriously infectious it will pick it up," she said.
"At the other end of the spectrum, when you're tailing off on your infection, the PCR test can keep picking up positives for weeks and weeks while a person people may not be infectious. At that point the rapid antigen will not pick them up."
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Antigen tests have been used widely to supplement PCR testing in the US and the UK, where people were also able to receive and use their own testing kits at home.
The TGA has strict regulations around antigen tests in Australia, and has yet to approve self-use. Its guideline said use required "the involvement of a suitably qualified healthcare professional".
But Dr Fahrer pointed to Queensland company Ellume, which has broken into the US market, as a potential template for their use in Australia.
Its home Covid test was linked to a Bluetooth analyser which automatically forwarded results, available within 15 minutes, to health authorities.
The test was approved by health authorities in the US, where it was available over the counter. Ellume has called for Australia to follow suit.
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