People are being warned to be very careful when they review the results of their rapid antigen tests.
A man in Victoria posted about his RAT test in a Facebook group showing an incredibly faint line.
While some people might think that a result like this would mean they're probably negative, the bloke known as Covid Pete said it probably means the opposite.
He revealed he'd developed symptoms before taking the RAT and, despite the faint line, it was confirmed he had coronavirus after taking a PCR test.
"Thought I'd share my original rat test with you all," he wrote in the group Covid Pete.
"When I started having symptoms, and others who were around me starting testing positive with their RAT test, I decided to do mine.
"As you can see, the second line of mine is very faint. You must take that second faint line as a positive test.
"It was confirmed a few days later that I was positive via PCR.
"So, if you see the faintest of lines, please be aware and cautious of your surroundings."
Others have said they experienced different results, including faint positive lines and then returning negative tests on a second go, but the consensus was still that people should be very careful with their assumed results.
Covid-19 testing facility overseer Dr Sally Shaw told 3AW a faint line should be considered a positive result on a RAT if the person has symptoms.
"We need to assume that if there's a faint line it's positive," she said.
"It only becomes pigmented - it only goes int that colour - if there's DNA in there."
Shaw said even if they are unable to get a PCR test people should isolate for seven days after returning a positive RAT.
"If you're just doing them because you want to go into work today and you're doing a rapid test every day, and you're perfectly well ... and you get a faint line, then I would isolate for one day and repeat it the next day," she said.
"If it's negative the next day, then you can say 'all right, you're free to go'. But with any symptoms, the faintest line is positive."
"Isolate for a week as the government has said, but please, in the second week, wear a mask, hand sanitise," she said.
"Be careful that second week - don't go to grandma's and vulnerable people."
The government changed isolation times last week, reducing the duration from 10 days to 7 days with a negative test returned on the sixth day.
Demand for the tests has skyrocketed following them replacing PCRs as the test of choice for Australians as testing clinics struggle with a massive backlog of test results.
There is concern that people have stopped doing PCR tests because of long wait times and the closure of testing facilities, meaning the actual number of positive cases in Australia could be much higher than those reported each day.
Experts believe the actual rate may be as much as ten times higher than the reported figures.
In a joint statement, the Public Health Association of Australia and the Australian Medical Association said the federal government should fund free RATs as well as a multilingual communication campaign on how to use them.
The organisations believe the tests are the best tool we have to combat the quickly spreading virus.
"RATs do, and must continue to play, an essential role in a pandemic that is looking increasingly out of control, PHAA chief executive Adjunct Professor Terry Slevin said.
"With the difficulty of getting a PCR test, many people just want to be confident they don't have the virus before they interact with others."
Featured Image Credit: Daniel Beckemeier / Alamy Stock PhotoTopics: covid, News, Scott Morrison, Australia