How long you test positive is determined, in part, by what test you use. PCR tests may show a positive result for up to three months, and rapid antigen tests may not detect the virus after nine days.

There are three different ways to test for COVID-19: PCR tests, antigen tests and antibody tests. Here are the differences.

Free at-home Covid tests can be ordered starting Monday. Here’s what you should know about when to test and what the results mean as new variants circulate.

Polymerase chain reaction (PCR) test kits for COVID-19 use what’s known as gene cloning – not reproductive cloning – to detect the presence or absence of the SARS-CoV-2 virus, but social ...

You can exhibit COVID-19 symptoms yet test negative due to early infection, low viral load, or immune response. PCR testing ...

If you use an antigen test, a positive result is reliable, but a negative test is not always accurate. If your antigen test is negative, take another antigen test after 48 hours or take a PCR test ...

Most people who contract COVID-19 likely won’t experience symptoms for more than two weeks at most, but could test positive even after that.

But lab-based PCR tests amplify the genetic material in a different way to this home-based test. So, strictly speaking, this new test is not a PCR test. The new test isn’t a RAT either.

A false positive result is possible with a rapid COVID-19 test. It happens when a person does not have COVID-19 but still tests positive for the disease.