Australia's medicines regulator has warned widespread use of rapid coronavirus tests could lead to infections being missed.
Therapeutic Goods Administration boss John Skerritt on Friday explained to a Senate committee the barriers for approving home use of rapid antigen testing.
He said PCR tests, which are widely used in Australia, were "exquisitely sensitive".
While useful in some settings, rapid tests are more likely to miss cases early or late in a person's infectious period or when there is a low viral load.
"That means they could get a negative rapid antigen test but then a day later actually end up being admitted to hospital with COVID," Professor Skerritt said.
Instructions for the 28 rapid test types approved for use in Australia are also an issue.
Unlike HIV or other home test kits, directions are written for professional rather than personal use.
"You need to do usability testing on average people," Professor Skerritt said.
"We had a couple of salespeople from a testing company visit us and they mucked up the tests.
"It's not only the performance of how well the test works with samples in lab but whether people can follow the instructions, a bit like cooking."
State health systems aren't linked to rapid tests meaning a positive result will not trigger the same response as a PCR test.
"These tests also tend to work more reliably when there's a higher prevalence of COVID in the community," Prof Skerritt said.
The TGA boss said while Australia's outbreaks were concerning, the level of virus and death in the community was still not comparable to overseas.
"The Australian testing environment is still what we call a low-prevalence situation, that's again where rapid antigen tests have to be used with greater care."
Rapid testing is widely used in the United Kingdom, United States, Europe and a number of other nations.
Prof Skerritt said some employers in Australia were using rapid testing effectively and revealed the TGA was in talks with the NSW government about use in schools.
He said it was false to suggest doctors or other health professionals needed to directly supervise their use.
But a connection between a person administering the test and someone who could provide advice was required.
