A Mornington Peninsula doctor has clarified some uncertainty about rapid antigen test (RAT) results.

Dr Sally Shaw says if even the faintest second line appears on a RAT, if you have symptoms, you should consider that as positive.

“With any symptoms the faintest line is positive,” she told Tony Jones, filling in for Neil Mitchell.

“It only becomes pigmented, it only goes into that colour, if there’s DNA in there.”

Dr Shaw urges people to in that situation to isolate for seven days, even if they’re unable to get a PCR test.

But for those doing routine RATs, Dr Shaw encourages doing a second test.

“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.

For those who’ve contracted the virus, Dr Shaw encourages taking extra precautions in the second week after a positive result.

“Isolate for a week as the government has said, but please, in the second week, wear a mask, and sanitise,” she said.

“Be careful that second week, don’t go to grandma’s.”

Press PLAY below to hear Dr Shaw on medical exemptions, RATs, and isolation