Dispelling common misconceptions with antigen testing
The COVID-19 pandemic brought with it a host of new information about the world around us. And it also brought about confusion about treatments, protocols, and more. And one area that’s been surrounded by debate is antigen tests. Are they accurate? Are they useful? Can they help curb the spread of disease?
The answer to all those questions is a resounding “yes.” In fact, when used correctly, antigen testing is an incredibly powerful tool that allows individuals, caregivers and health care providers to take fast action and effectively reduce disease transmission—and save lives.
Antigen tests versus PCR tests: which should you use, and when?
Antigen tests and polymerase chain reaction (PCR) tests are both valuable diagnostic measures. And, when used correctly and at the appropriate time, they can each have a tremendous impact on our ability to mitigate the spread of COVID-19.
PCR tests are considered the “gold standard” for COVID-19 testing because they are the most accurate for diagnosing the virus1. The test is done in a lab and detects the presence of viral RNA in nasopharyngeal swab. In this test, the material from the swab is combined with a reverse transcriptase or DNA polymerase, a substance that causes RNA particles to multiply, eventually producing a positive result. These tests are so accurate they could ultimately detect the presence of a single RNA particle, which helps us get the most detailed information for tracking and studying the virus. The downside, however, is that PCR tests can detect the remains of the viral RNA even after a person has recovered from the virus, producing a positive result even though the person is no longer infectious2.
Rapid antigen tests analyze nasopharyngeal swabs to detect proteins specific to COVID-19. Unlike the PCR, which can detect minute amounts of the virus, antigen tests are designed to detect high viral loads, which occur in the body when a person is most infectious. Antigen tests are also faster than PCR tests, producing results within 15 to 30 minutes without having to be sent to a lab. And they don’t need special equipment; in fact, people can safely perform the test from their own home, making it an accessible option that can be incorporated into one’s regular routine.
Accuracy you can count on
Because rapid antigen testing detects proteins produced specifically by COVID-19, a positive result is a sure indicator of the presence of the disease. And while accuracy can vary depending on the brand of the test used, Innova Medical Group’s rapid antigen tests are sensitive with 99.68% accuracy on high viral load patients (viral load >= 100,000 copies/mL)3.
And this isn’t just theory. In a real-world study conducted in the UK, millions of rapid antigen test results showed a specificity of 99.9%—and perhaps even higher. In other words, for every 1,000 tests performed, there is less than one false positive4. That means if a person tests negative, they’re not infectious and are at low risk of spreading the disease. And if they test positive, they can isolate themselves quickly, thereby breaking the chain of transmission and reducing the spread of the virus.
Great Britain has made rapid antigen testing a regular part of its COVID-19 protocol, with testing recommended twice a week every week and free tests being made available for the population. This has proven particularly invaluable when it comes to detecting asymptomatic cases; 1 in 3 people infected with COVID-19 never get sick and can end up spreading the virus unknowingly5, but regular and widespread testing means those cases can be caught and, as a result, outbreaks can be prevented.
Antigen testing provides rapid results
COVID-19 is highly contagious and can spread rapidly through a population, as we’ve seen in cities and countries across the world. And with something as fast-moving as COVID-19, the only way to combat it is to work equally quickly.
That’s where rapid antigen testing can make the most impact. For example, the CDC has recommended using these tests in congregate settings, like nursing homes6, where social distancing can be difficult and just one infected person could mean catastrophe for the health and safety of residents and staff alike. In those cases, repeat testing and near-immediate results mean people can act quickly to implement prevention and control measures, thereby reducing the risk of transmission.
The results of a study published in October 2020 also concluded slow wait times for test results were hampering ability to curb the spread of COVID-197. The average wait time was 2.7 days, while some were waiting as long as 4.4 days. The ramifications? The longer someone waits to find out they’re positive, the more chances they might have to spread the disease, and the more difficult it becomes to adequately trace whom they’ve been in contact with8.
Rapid antigen testing also prevents people from isolating unnecessarily. For instance, someone might miss work or school while isolating and waiting for their results, only to find out they tested negative. Or, as we noted earlier, PCR tests can produce positive results even though a person is no longer infectious, resulting in isolation protocols that inconvenience the individual without effectively reducing the spread of disease.
A lifesaving tool
Despite misconceptions surrounding antigen testing, this test remains a critical tool for reducing and even stopping serious viral outbreaks. Safe, reliable, and accessible, rapid antigen testing makes it easy to quickly identify people when they’re at their most infectious, even if they’re asymptomatic, allowing them to take steps to isolate themselves, stopping the chain of transmission—and saving lives.
1https://my.clevelandclinic.org/health/diagnostics/21462-covid-19-and-pcr-testing
2https://my.clevelandclinic.org/health/diagnostics/21462-covid-19-and-pcr-testing
3https://innovamedgroup.com
4https://www.gov.uk/government/news/new-analysis-of-lateral-flow-tests-shows-specificity-of-at-least-999
5https://www.gov.uk/government/news/new-analysis-of-lateral-flow-tests-shows-specificity-of-at-least-999
6https://www.cdc.gov/coronavirus/2019-ncov/lab/resources/antigen-tests-guidelines.html
7http://www.kateto.net/covid19/COVID19%20CONSORTIUM%20REPORT%2017%20TEST%20OCT%202020.pdf
8http://www.kateto.net/covid19/COVID19%20CONSORTIUM%20REPORT%2017%20TEST%20OCT%202020.pdf