We’re here to clarify some of the misconceptions around the Antigen vs. PCR test and to help you understand the difference between rapid antigen tests and the “gold standard” PCR tests that have been prominent for most of the pandemic.
Why does this difference exist? In a way, in detecting two different targets, these two tests are also serving two different purposes. In looking for a target that is essentially representative of whether or not the virus is “live” and able to infect cells, a rapid antigen test is a tool to determine whether or not you can transmit the virus to other people, spreading the disease. This window is relatively short (within the 10-day window recommended by the CDC to isolate or quarantine if you’ve been infected or exposed). On the other hand, RNA can persist for a relatively long time, well beyond that 10-day window, because of its decay rate. Even if this is in small amounts, the sensitivity of a PCR test means that the residual, “dead” virus can be picked up — and this is well beyond that 10-day window of concern.
Thus, while both of these tests are important and they both come with caveats, a rapid antigen test as an instantaneous snapshot is more helpful to determine whether or not you will be transmitting virus to others and spreading disease. In a sense, the difference in use, the difference in targets, and the difference in the rate that these two targets decay and “disappear” makes it hard to compare the two tests — while both are useful, they serve different purposes.
The CareStart™ COVID-19 Antigen test has not been FDA cleared or approved. This test has been authorized by FDA under an EUA for use by authorized laboratories and at the Point of Care by medical professionals operating under a CLIA Certificate of Waiver, Certificate of Compliance, or Certificate of Accreditation.
The CareStartTM COVID-19 Antigen test is manufactured by Access Bio Inc. for Intrivo. CarestartTM is a trademark of Access Bio, Inc.