The first reported case of COVID-19 in the United States came on January 20, 2020, though it is probable there were cases already in existence. Testing for the virus quickly became the first vital step toward containment. As testing became more accessible, we began to see the full scope of what we were dealing with.
The experts agree that COVID testing will be with us for a long time, possibly like the flu. It’s important to know the different tests that exist so you can make informed decisions with your healthcare provider.
Katie Bennett, Ph.D., Associate Professor of Molecular Pathology in the TTUHSC Department of Laboratory Sciences and Primary Care, walked us through the different types of tests and what makes them different. She also spoke about the future of testing now that vaccines are here.
“There are three major kinds of tests, categorized on the chemistry that is used to assess COVID, looking for SARS-CoV-2, the virus that causes the disease,” Bennett explained.
Molecular (PCR) COVID-19 Testing
Bennett said that molecular (PCR) testing is the gold standard test for COVID-19. PCR testing is highly sensitive. It can pick up miniscule amounts of virus, giving it more ability to accurately provide a positive test result. Tiny amounts of viral RNA can be detected with this test, making it the top of the list of COVID testing choices. The PCR was the first test to be available on the market.
“[The PCR test is] what was being done early on when you’d hear about the swab that tickles your brain,” Bennett said. A positive PCR test result means you have the virus and are likely to be contagious.
Antigen COVID-19 Testing
This is the newest type of test and is becoming more common and widely available. It finds SARS-CoV-2 by searching for a protein that the virus makes. Bennett referred to the familiar white-and-red illustrations of COVID often used on the news.
“The spikes on the outside of the virus are proteins that can be detected with the antigen test,” she said. These tests are taken with a nasal or oral swab, similar to a strep test. The biggest difference (besides not having your brain tickled) is that results come much faster, at the clinic or in a drive-through testing environment. The disadvantage is that it’s not as sensitive as the PCR test, meaning patients need more of the virus in their body for it to be detected.
COVID-19 Antibody Testing
The COVID antibody test is different because it isn’t used for diagnostic purposes.
“The antibody test is a way to know if you’ve been exposed to SARS-CoV-2 in the past,” Bennett explained. This test is looking for the body’s reaction to previous infection. When infected, your body produces antibodies.
Variant Strains of COVID-19
Bennett says there are significant concerns about the ways variant strains (UK, South Africa, US) of the coronavirus will affect testing. She said much is still unknown.
“With certain lab tests, if you have the wrong mutation in the wrong place, it could affect the test,” she explained. “We don’t know where it will go in the future as far as which variant will be predominant.”
This has presented concern about vaccines being less effective, but Bennett said there is still some protection, even if you get a variant strain.
“Your immune system is not all or nothing,” she assured. “It will lessen the seriousness of the disease.”
So, getting vaccinated is still very important.
Bennett believes that testing for variant strains of COVID will become more widespread in the future as we learn more about them.
“Right now, surveillance detection will continue growing,” she said. She says the goal is to get as much surveillance as possible to be ready when the virus mutates.
Do the COVID-19 Vaccines Affect Testing?
Bennett explained that the COVID-19 vaccines can impact the antibody test, as the purpose of the vaccine is to stimulate production of antibodies.
“If you’ve been vaccinated, it takes a couple weeks to produce antibodies,” she said. After that time period, you could receive a positive antibody test, but the vaccine will not cause a positive molecular or antigen test result. Ideally, Bennett said, vaccination will be widespread, and the incidences of the virus will decline.
What Does the Future of COVID-19 Testing Look Like?
Bennett explained that COVID testing is here to stay.
“This is going to become another viral test that we put into the repertoire of lab tests,” she said. It’s possible that this could be “the new flu,” she said, cycling through during a particular season, like how influenza behaves. Bennett said that, in the future, patients with flu-like symptoms may be tested for both the flu and COVID-19. She predicts, “One test, both diseases.”
Bennett is passionate about the importance of being informed as a patient. Ask your providers what type of COVID testing they are administering. Be an advocate for yourself by understanding the pros and cons of each lab test. Education about COVID tests will better prepare you to receive the results.