When should I get a PCR test instead of using an at-home test?īoth tests are good. It’s also important to collect the sample correctly, so Tran recommends that you follow the package directions on at-home tests carefully to get the most accurate results. “If you’re feeling symptomatic, and you think you were exposed, then I would say test again 12 to 24 hours later,” Mina said.

“So if you still suspect then you might want to check it again. “But again, there’s no such thing as a perfect test,” Tran said. “But if you’ve gone from having a really dark line to a much fainter line, then you should know that you’re likely still able to transmit the virus, but the potential for that transmission is less.”Ī PCR test at a doctor’s office or laboratory has a better chance of picking up low concentrations of the virus, so a negative PCR test might be more reliable. “You should really assume that you are highly infectious and do everything you can under the sun to not infect other people,” he said. If the test results show up very quickly and the line is very dark, it could indicate you have a great chance of transmitting the virus to others, he added. “If you have enough virus to turn a rapid antigen test positive, you have a lot of virus there,” Mina said. If you get a positive result on a rapid test, it’s most likely that you are contagious and can spread the virus. Does a positive rapid test mean I’m contagious? The changes that lead to new variants tend to occur in the spike protein. and globally detects a protein called the nucleocapsid, which is stable and just doesn’t, hasn’t seen a lot of mutations,” Mina said. “Almost every rapid test that’s authorized in the U.S. That’s because the mutations are happening in a different part of the virus than the portion detected by rapid tests.

“We’ve actually never seen a deterioration in accuracy of the tests, given any new variants,” he said.

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