Australian antigen test

Author • Thea van de Mortel Professor, Nursing and Deputy Head (Learning & Teaching), School of Nursing and Midwifery, Griffith University Disclosure statement Thea van de Mortel teaches into the graduate Infection Prevention and Control program at Griffith University. Partners The Conversation UK receives funding from these organisations View the full list Languages • • English How the tests work In Australia, PCR tests are used to diagnose SARS-CoV-2 infections. This test looks for SARS-CoV-2 genetic material. RT-PCR converts viral RNA to DNA and amplifies the genetic sequence, making billions of copies, to a point where these copies can be detected. Because the test can amplify tiny amounts of viral genetic material, it’s considered the gold standard and can detect infection in earlier stages than other tests like rapid antigen tests. Here’s how PCR testing works. Rapid antigen tests instead detect Rapid antigen tests are: • quicker than PCR tests (15-20 minutes versus hours to days to get a result) • can be done in the home compared to having to line up and wait for a swab, which then has to be analysed in a laboratory. But they’re less sensitive than a PCR test because there is no amplification process. Here’s how to do a rapid antigen test at home. How effective are they? While both tests are more likely to correctly detect an infection when the person’s viral load is high, PCR tests are more sensitive than rapid antigen tests. An This rose to 100% when people were t...

The TGA has categorised 15 approved Covid rapid antigen tests into three levels of sensitivity, but infectious disease physician Paul Griffin says any approved test is worth using. Photograph: Lukas Coch/AAP The TGA has categorised 15 approved Covid rapid antigen tests into three levels of sensitivity, but infectious disease physician Paul Griffin says any approved test is worth using. Photograph: Lukas Coch/AAP As Covid case numbers continue to surge across the country and testing wait times blow out, people are increasingly using rapid antigen tests. They are a convenient alternative to queueing for traditional polymerase chain reaction (PCR) tests and an extra precaution before attending gatherings in the lead-up to Christmas. 04:55 How to use a Covid-19 rapid antigen testing kit – video The federal department of health says rapid antigen tests are a faster way of getting a result, but don’t replace PCR tests. So, which tests can you trust, and how much are they? Quality The Therapeutic Goods Administration (TGA) has approved The TGA based its judgment of the performance of each kit on studies done by the manufacturer that show the positive percent agreement (PPA) – the percentage of individuals that produced a positive test result using a rapid antigen test, in comparison with a positive result by PCR test. Read more The TGA sets the minimum clinical sensitivity a testing kit must achieve before it is approved at 80%, which it labels as “acceptable sensitivity”. A kit ...

From Monday, Australians can buy rapid antigen Covid-19 tests at retail stores including supermarkets and pharmacies, and also online. Previously, only health professionals were able to administer them. Australia’s drugs regulator, the Therapeutic Goods Administration (TGA), has so far approved nine different home rapid antigen tests for sale. They cost roughly $30 for a packet of two, and between $50 and $100 for five, depending on the retailer and brand. They have a shelf life of about two years. How do they work? Currently most people are diagnosed with a PCR test, usually administered by a doctor or nurse, which involve taking a swab of the nose and throat. PCR tests are government-subsidised and are the gold standard for diagnosis – they can diagnose Covid-19 even in the early stages of the virus, sometimes even before someone feels unwell. They detect the virus almost 100% of the time when it is is administered properly. The downside is the sample needs to be sent to a laboratory, taking between several hours to a couple of days to get a result. Meanwhile, rapid antigen tests are most useful for detecting the virus when someone has a high viral load. Outside of this phase especially, they are not as accurate as PCR tests. There is a higher risk of false positive and false negative results. Read more The benefit of rapid antigen tests is they are quick, convenient, and don’t require a laboratory. The home tests involve self-performing a nasal swab using a small cotton...