Feeling positive but testing negative? Perhaps you’re RAT testing wrong.
For the past two years, being tested for Covid-19 meant having a stick shoved so far up your nose it felt like it was touching your brain. Polymerase chain reaction (PCR) tests have been the primary method of detecting positive Covid-19 cases for around two years, but with the significant increase in recent case numbers, the efficiency of these tests has dramatically decreased.
Rapid antigen testing (RATs), a fast response, do-it-yourself Covid-19 test has now become the primary method of detecting Covid-19. RATs have significantly eased the pressure on PCR testing, speeding up the entire process and helping to confirm thousands of positive cases every day where PCR tests would struggle to do so.
Although RAT tests are winning in the speed department, their accuracy levels are sub-standard next to their PCR counterparts. Many people have been testing negative with RATs despite being Covid-19 positive, which leads to unnecessary community transmission.
“I hung out with friends who had positive close contacts after they said they tested negative on RAT a few times. I then came down with [Covid-19], so I think that there is a big possibility that some people aren’t testing properly or maybe the viral load just takes more time to show up on some people than others,” said recent graduate student, Courtney Purcell.
“I automatically assumed the RAT test should be done in the same way the PCR is. I was trying to push this swab as far up my nose as I could handle, but it turns out that’s not how it’s done at all,” said Naoko Ito, a Massey design student.
Microbiologist and expert Siouxsie Wiles said, “My top tip is to go low and slow. Basically, what you don’t want to do is be heading up towards your brain, you want to head right back, kind of straight. Remember, low and slow.”
A government-issued instruction manual on RAT testing suggests inserting the swab only 2-3 cm from the edge of your nostril, then slowly rolling the swab five times over the surface of each nostril. Once the swab has been taken, place it into the extraction vial and rotate it vigorously at least five times. Remove the swab by rotating it against the vial, while squeezing the sides to release liquid from the swab. Once the vial is closed, flick the bottom of the tube before squeezing the required number of drops from the kit instructions onto the test.
Asides from not testing correctly, false-negative tests are also being produced because there is not enough viral load for the test to detect.
A key thing to remember is that symptomatic doesn’t always mean infectious. For vaccinated people, symptoms kick in quickly after exposure despite high levels of the virus not having entered the body yet. Therefore, many people are reaching for a test too soon to produce a positive result. For the unvaccinated, symptoms are slower to show yet the virus grows faster. This is because the body’s immune response is slower to react to the virus.
Siouxsie Wiles recommends that, if showing symptoms, you “do get a test straight away, because if you do have enough virus there then it will detect it. If it comes back negative but you still have symptoms, then wait a day or so and try another test.”