COVID-19 Tests Comparison

With the increasing amount of COVID-19 tests in the market, we break down the two most widely used diagnostic tests to detect COVID-19.
A side by side comparison of COVID-19 TESTS

The Difference between PCR and Antigen Tests

Community Labs proudly offers PCR testing, FDA’s gold standard. Antigen testing is also a popular form of testing for COVID-19. Both are diagnostic tests designed to detect current infection. Here’s a side-by-side comparison:  



Test Accuracy
Highly accurate, considered FDA's gold standard
More likely to miss an active COVID-19 infection compared to molecular tests. If you get a negative result but have symptoms of COVID-19, your health care provider may order a molecular test.
Detection Method
Detects the presence of the virus's genetic material using a lab technique called polymerase chain reaction (PCR) where many copies of the DNA are made so it can be easily detected.
Detects specific proteins on the surface of the SARS-CoV-2 virus
Test Administration
Nasal or throat swab, saliva sample
Nasal or throat swab, saliva sample
Turnaround Time
Within 24 hours
Less than an hour
Commonly known as
Viral Test, Molecular Test
Rapid Test

Frequently Asked Questions

How is an antibody test different from a PCR or antigen test?

An antibody test is not a diagnostic test. It is not intended for people who currently are experiencing COVID-19 symptoms and does not check for the presence of the virus. Antibodies are proteins that help the body fight infections and may remain in the body for some time. Antibody tests are used to detect these antibodies to determine if a person was previously infected with the virus that causes COVID-19.

If I have symptoms, when should I get tested?

If you have symptoms, you should get tested right away through your healthcare provider. If your test returns a negative, they will likely require you to take a second PCR test for assurance.

If I think I have been exposed, when should I get tested?

You should immediately quarantine before you get a test. On average, it takes 4-5 days after someone is infected with COVID-19 for them to show symptoms. It is recommended to take a test 4-5 days after exposure and another test 14 days after exposure.

How frequently should I get tested?

If you are interacting with people through your job, visiting family and friends, traveling, we recommend testing weekly for “assurance.”

Why should I test if I don’t have symptoms?

According to a study done by PNAS, silent disease transmission during the presymptomatic and asymptomatic stages are responsible for more than 50% of the overall attack rate in COVID-19 outbreaks. Furthermore, such silent transmission alone can sustain outbreaks even if all symptomatic cases are immediately isolated. It is for this reason that testing is one way to lower the risk of spreading COVID-19. 



Together we can make San Antonio the safest city in America.


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