Since the beginning of the COVID-19 pandemic, we’ve all had to learn a lot of new vocabulary and terms. Antigen tests are one of the tools that healthcare professionals use to diagnose and screen for SARS-CoV-2. But what exactly are COVID-19 antigen tests and how do they work? We’ll answer this question and more, including taking a look at the pcr covid test vs rapid test, in this short guide.
Antigen tests are a type of test that is commonly used when diagnosing respiratory pathogens, like influenza and respiratory syncytial virus (RSV). When SARS-CoV-2 virus appeared, the U.S. Food and Drug Administration (FDA) granted emergency use authorization (EUA) for this type of testing to be applied to COVID-19.
The COVID-19 antigen test is also known as the “rapid response” test or “rapid test” due to the short amount of time that it takes to receive a result. It can be as little as 15 minutes to get a response from the antigen test. However, due to accuracy concerns, many doctors will have people take a PCR test to confirm a negative or positive result. Antigen tests are typically cheaper and faster to perform than other types of tests, meaning it can be a great screening tool and ease the burden on overwhelmed testing systems in the midst of a pandemic.
The difference between the COVID-19 antigen test and the PCR test is what the test is looking for, how it detects it, and how long it takes.
With the rapid antigen test procedure, a healthcare provider takes a nasal swab and then puts it into a solution. This solution detects certain proteins in the virus, and the healthcare provider can know in minutes if that protein is present. The presence of the protein means that the patient is most likely positive for COVID-19, and should follow isolation guidelines from the CDC. With COVID-19 antigen tests, there is an increased chance of false-negatives—meaning the patient is positive for the virus but tests negative—and a negative test may need to be confirmed with a PCR test.
The PCR test, on the other hand, works by looking for the genetic material of the virus. Once the patient is swabbed, that sample is sent to a lab where a technique called polymerase chain reaction (PCR) is used to see if the genetic material of the SARS-CoV-2 virus is present. PCR tests are considered the ‘gold standard’ of COVID-19 testing because they are considered more accurate than antigen tests.
With the PCR test, because it often has to be sent off to a lab to perform the analysis, results typically take anywhere from 24 hours to three days, depending on the capacity of the lab. COVID-19 antigen tests only take about 15 minutes on average, so the difference in testing time can be rather significant. PCR tests are fantastic for an accurate result, while antigen tests are well suited for screening large numbers of people.
Covid antigen test accuracy is a tricky thing to nail down. This is because we don’t have all the information, and studies are still being performed to gather data and understand the testing process better.
That being said, a group of scientists looked at 64 studies of antigen test accuracy, and found that in people with confirmed COVID-19, antigen tests correctly identified COVID-19 infection in an average of 72% of people with symptoms and in 58% of people without symptoms. These tests were most accurate when used in the first week after symptoms developed, most likely because that is when people have the highest levels of the virus in their system.
These same studies show that COVID-19 antigen tests vary in sensitivity, and that PCR tests still seem to be a more accurate option when testing for SARS-CoV-2.
While antigen tests can be a valuable screening tool, PCR tests are the most accurate and reliable way to determine if you have contracted COVID-19. At BioCollections, our turnaround time for PCR tests is only 13 hours, and we’ve performed over 300,000 since the beginning of this pandemic. We know how important it is to get your results back and be able to trust that you have the correct information about your health. Because of that, our COVID-19 panel also includes information about the variant and checks for flu strains at no additional cost. For more information about COVID-19 testing, Contact us today for more information about our locations and testing hours.