A Rapid Antigen Test (RAT) is one of the quickest ways to test if you have COVID-19 infection or not. It is mostly used in situations when a patient needs it for quick clarity. The test is being widely used in the US, European countries, and India. Now the state of South Australia has also started doing Rapid Antigen Tests on interstate travellers coming into the southern province of the country. Here, we will be explaining all you should know about these tests:
What is a Rapid Antigen Test?
An antigen test is a method of detecting an active infection by SARS-CoV-2, a variant of coronavirus that causes COVID-19. These tests look for antigens, which are protein markers found on the outside of a virus. The test is performed on a sample that is taken by swabbing inside your nose. The rapid antigen test is the quickest way of detecting a virus – in order to prevent contagion. It is not only used to detect viruses, but to detect pregnancy as well.
How do you do Rapid Antigen Test?
A swab is inserted into your nose to collect samples of mucus. Alternatively, it can be inserted into the throat to collect the sample of sputum. These swabs are then thoroughly mixed with liquid – drops of which are poured on paper strip that detects the virus. After this you will have to wait for 20 minutes. If the paper strip shows two lines, you are tested positive for the virus. If the paper strip shows single line, you are negative.
Are they foolproof?
In the words of a senior doctor: “if your rapid test comes positive, then you are positive and there is no second thought on that. However, if your rapid comes negative, you are not sure shot negative – you will have to go for RT-PCR test to double check it.” For people with symptoms of COVID-19, an average 72% of the tests correctly gave a positive result. The 95 percent confidence intervals were 63.7% to 79%, meaning that the researchers were 95% confident that the average fell between these two values, according to studies. The researchers found that people without COVID-19 symptoms correctly tested positive in 58.1% of rapid tests. The 95% confidence intervals were 40.2% to 74.1%, the researchers suggest. The chances of rapid antigen test showing a false positive is very rare – and as per the studies, rapid tests correctly gave a positive COVID-19 result in 99.6% of people.
What is an RT-PCR test?
RT-PCR stands for Reverse transcription polymerase chain reaction. The test is a nuclear-derived method for detecting the presence of specific genetic material in any pathogen, including a virus. Earlier, the method used radioactive isotope markers to detect targeted genetic materials. However, later on, it was refined, which led to the replacement of isotopic labelling with special markers, most frequently fluorescent dyes. The technique of RT-PCR allows scientists to see the results almost immediately while the process is still ongoing, whereas conventional RT–PCR only provides results at the end of the process.