The Difference Between PCR and Antigen Tests
COVID-19 testing is now a regular part of life for many individuals across the country. As the Omicron variant emerges as the dominating strain of the SARS-CoV-2 virus, the unvaccinated and vaccinated alike are relying more and more on weekly (sometimes daily) tests to work, travel, or generally engage with the community.
Lincoln Urgent Care is dedicated to offering our patients the best healthcare options available. As of January 2022, there are two broad categories of testing available to the public: PCR tests and antigen tests. They are both considered ‘diagnostic tests,’ which means either will be able to tell you if you are currently infected with the coronavirus at the time of testing.
While CDC guidelines on isolation and/or quarantine will continue to evolve, understanding how these tests work is information to be aware of. A lot of our patients want to understand: What is the difference between PCR and antigen tests?
WHAT IS A PCR TEST?
We touched on this in our last post on the topic:
“A polymerase chain reaction (PCR) test is performed to detect genetic material from a specific organism, such as a virus. The test detects the presence of a virus if you are infected at the time of the test. The test could also detect fragments of the virus even after you are no longer infected.”
PCRs determine whether the virus is present by looking for the presence of the virus’s genetic material. Most of the time, PCR tests are extremely accurate; the only drawback being the amount of time between getting tested and getting a definitive answer.
After a sample is extracted (commonly using the deep nasal swab technique, although samples from the throat or saliva may be tested also), it’s sent to a laboratory for processing. Typically, that process lasts anywhere from 1-3 days.
We’re pleased to offer PCR testing with results in 2-3 days. For those looking to obtain results faster, we suggest our new Accula SARS-CoV-2 test and a nasal swab, where we can return the results of your PCR test in as little as 30 minutes.
WHAT IS AN ANTIGEN TEST?
According to Harvard Medical School:
“Antigen tests detect specific proteins on the surface of the coronavirus. They are sometimes referred to as rapid diagnostic tests because it can take less than an hour to get the test results. Positive antigen test results are highly specific, meaning that if you test positive you are very likely to be infected.”
Antigen tests, while offering results within 15-30 minutes with great accuracy, can return a higher rate of false negatives than the PCR test. Once infected, a patient ‘sheds’ the viral load in their system; these levels can vary widely over the course of infection. Test too early (or too late) and it may result in a false negative – but, antigen tests will detect active infection. Antigen testing is still widely regarded as the primary line of defense because they offer results in minutes, doesn’t require laboratory processing, and costs less out-of-pocket. You can even perform antigen tests at home – the Department of Health and Human Services will now send you four for free if you visit CovidTests.gov (tests expected to ship within 7-12 days).
However, you don’t have to wait. Come see us and we can perform antigen tests on-site at Lincoln Urgent Care.
THE DIFFERENCE BETWEEN PCR AND ANTIGEN TESTS
Generally, the differences are technique, time, and usage. The cost often varies too.
- An antigen test is a rapid test, while the PCR test traditionally takes a few days to return results.
- An antigen test looks for specific proteins found on the surface of the virus, while a PCR test seeks out and amplifies the presence of the virus’s DNA material.
- PCR tests are preferred/required for international travel.
- Our price for an antigen test (self-pay) is $150; for PCR, the test is $200.
We offer both PCR and antigen tests at Lincoln Urgent Care.
RAPID PCR TEST LINCOLN, CA
Lincoln Urgent Care can now also perform rapid PCR tests by appointment only. This new test returns PCR results in as little as 30 minutes. If you don’t see availability in our appointment portal it means our schedule is fully booked. Please continue to check our online openings as we do our best to keep up with the demand.