What to Know About Rapid COVID Testing
By Nancy LeBrun and Susan McBratney, PhD for Healthgrades.com
As the United States continues to grapple with the COVID-19 pandemic, the testing initiative remains contentious and uneven. There have been concerns about availability, accuracy, objectives, and delays in results. Could the wider introduction of a rapid COVID test help? There are pros and cons to this form of COVID testing, which delivers results in minutes but has less reliable results than other COVID tests. Availability of rapid testing varies by location, so you may or may not have access to one. Be prepared with what’s known so far about rapid COVID testing.
COVID tests fall into two main categories:
Diagnostic tests tell you whether you have an active COVID infection. Currently, there are rapid antigen tests and more precise molecular tests. The main molecular test in use is based on PCR (polymerase chain reaction), but there are other types of diagnostic molecular tests.
Antibody tests tell you whether you had a prior COVID infection. Again, there are rapid tests as well as conventional laboratory serology tests.
How a Rapid COVID Test Works
A rapid COVID test is a type of diagnostic test. Rapid tests usually measure viral antigens, which are substances that tell your body to produce an immune response to an infection. Antigens are not the same as antibodies, which your immune system produces in response to signals from antigens. Trained personnel in a variety of settings can administer a COVID rapid antigen test.
The other type of diagnostic test is the PCR test, which detects molecules of viral genetic material (RNA). It is labor intensive and performed in an accredited laboratory. The molecular test is the standard diagnostic test for COVID, but you may have to wait several days or more to get the results.
There are other, non-PCR types of molecular tests to detect coronavirus RNA, oftentimes with a quicker turnaround time. One of the tests in use for diagnosing active coronavirus infection involves LAMP (loop-mediated isothermal amplification). It is a rapid molecular test, typically for use in a clinical setting like a hospital or nursing home. An at-home COVID-19 test using LAMP was recently issues an emergency use authorization (EUA) by the FDA (Food and Drug Administration), available in spring of 2021.
Rapid antigen, antibody and molecular tests are so-called “point-of-care” tests, where results are returned at the time the sample is taken, usually within 15 minutes.
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