PRC vs. antigen test: What kind of COVID-19 test is best?

As the omicron surge continues and the government begins mailing out free at-home COVID-19 tests, it can be confusing which test to use and when to use them.

The chief medical officer of Parkland Health said the at-home tests offer easy and fast results, but they are not always better.

"These billion tests that can be requested and that are getting sent out, those are called antigen tests. And they are really fast, but they only work when you have symptoms. If you don’t have symptoms, those tests are basically like a coin flip. So, I would definitely not suggest using those rapid antigen tests if you are just wondering if you have been exposed to COVID," Dr. Joseph Chang said.

Dr. Chang said if you have symptoms, the rapid antigen tests that offer results in about 15 minutes are about 85% accurate.

He recommends getting a PRC test that offers results in a day or more if you do not have symptoms or if you want to make sure you are no longer contagious after testing positive.

PCR tests are only available at testing sites and not at home.

COVID test

FILE - In this photo illustration, a COVID-19 antigen home test kit shows a negative result.

"The PCR is always going to be better. But if you do want to use those rapid tests, my advice would be to do two of them on successive days," Dr. Chang said. "If they are both negative, then you can feel pretty good about it."

As far as when to test, Dr. Chang said you should only test when you need to such as when you are feeling sick or have been directly exposed to the virus. Especially with the rapid tests, overtesting can be bad for your psyche. 

"Number one, it’s just going to freak you out. Either that or give you a false sense of security. And number two, really they are not very accurate if you don’t have symptoms. So, taking them all the time, it’s really just going to freak you out," he said. "If you feel sick, use your best judgement. If you’ve got a runny nose, if you’ve got a cough, you’re coughing up stuff or you’ve got a fever, those are reasons to take a test. But if you’ve just got a headache, take a couple Motrin and see if it gets better."

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