Antigen Covid Tests: How Accurate Are They?

Living in a COVID centered world has been challenging for everyone. A lot has changed for the way we navigate our interactions and a whole lot more. We’re even questioning the accuracy of testing, incubation periods and transmission data. The idea of using a rapid test and not getting reliable results is scary for those who are at a higher risk of contracting the virus and experiencing severe symptoms. And there’s so much information that it’s hard to know what’s trustworthy and what’s not. So here’s some information that can put your mind to ease regarding the accuracy of rapid antigen Covid tests which have come into question for some people. 

Antigen Covid Tests: How Accurate Are They?
[image: pexels by tima miroshnichenko]

Types of Antigen COVID Tests

When you compare COVID saliva test accuracy to that of the more invasive nasal swab rapid tests, you’ll begin to see that all antigen Covid tests are not the same. Although they all are designed to detect the presence of the Sars-Cov-2 protein, some of them do a better job of identifying COVID in someone who is at high risk of transmitting the virus. The problem with accuracy seems to have more to do with the lag time of the virus. The more the virus replicates inside of cells, the more likely it is to shed the protein. But when the virus is in the earlier stages of replication there may not be enough viral protein for a rapid test to pick up. Some antigen tests have the ability to detect the protein days before symptoms appear while others are more accurate once symptoms appear. So the accuracy of these lucira covid-19 & flu test online tests will often depend on what stage of development the virus is in.

Rapid Test Accuracy

Cochrane conducted a study on just how accurate these rapid tests are. Some of their main takeaways were that different tests had different accuracy rates; the amount of time the virus incubated impacted test results; and whether or not the participant was exhibiting symptoms also played a role in having some influence on the antigen test’s reliability. There are plenty of factors that have the potential to derail antigen test results but in general, they are good indicators of whether or not the virus is present in a body. 

PCR or Molecular Test

A molecular test or PCR test is testing genetic material rather than testing for COVID-19 proteins. The drawback here is that these tests will sometimes pick up trace amounts of COVID RNA long after a patient is no longer contagious. Typically, you won’t get the results from these tests for about 24 hours, but these tests have a much higher accuracy. The PCR tests used at UC-Davis  are nearly 100% accurate. But there are some PCRs that have false negative rates as high as 20%.

The fact is that some tests are more sensitive to the COVID protein and will yield more accurate results, while others may miss it if there’s not enough viral load to detect. If indeed you are concerned about accuracy, do not be afraid to try a different test or to have your healthcare provider order a PCR or molecular test for you.