What is a COVID rapid test, and how does it work? Until now, the majority of COVID-19 rapid diagnostic tests have been done with a nasal or throat swab. They detect a protein that is part of the coronavirus. These rapid tests are particularly useful for identifying a person who is at or near peak infection.

What are rapid diagnostic tests?

Rapid diagnostic tests (RDT) detect the presence of viral proteins (antigens) expressed by the COVID-19 virus in a sample from the respiratory tract of a person.

If the target antigen is present in sufficient concentrations in the sample, it will bind to specific antibodies fixed to a paper strip enclosed in a plastic casing and generate a visually detectable signal, typically within 30 minutes.

Are COVID-19 molecular tests more accurate than antigen tests?

Molecular tests are generally more accurate and mostly processed in a laboratory, which takes longer; antigen tests—which are sometimes referred to as 'rapid tests'—are processed pretty much anywhere, including in doctor's office, pharmacies, or even at home.