What is a rapid COVID-19 test?

What is a rapid COVID-19 test?

A rapid test is a type of extra quick test for infectious diseases. In general, the goal of a rapid test is to produce results within minutes or hours without specialized lab equipment. Rapid testing for COVID-19 is an important step to increasing the number of people we can test and getting results back faster. This allows doctors to give people immediate follow-up care and quarantine directions. 

Some rapid tests have recently been approved by the US FDA through an emergency use authorization, and they are now widely available. Most rapid tests in development are antigen tests, although there are also other approaches. Some scientists argue that even simpler, cheaper tests should also be approved to allow for daily, at-home testing.

What’s an antigen test?

Antigens are anything that triggers your body’s immune system to produce antibodies. Some antigens are recognizable parts of germs like a nose is a recognizable part of someone’s face. Antigen tests for COVID detect parts of the novel coronavirus. The antigen test uses a chemical reaction that causes a color change. This color change alerts you that a person is infected. You might be familiar with rapid tests for strep throat, which detect parts of the bacteria that cause strep. The FDA recently approved a $5 COVID-19 antigen test from Abott that provides test results in just 15 minutes.

The primary concern is that rapid antigen tests may give more false negatives than the “gold standard” PCR test. Antigen tests work best early in infection, when the amount of antigen is highest. If you’re tested later in infection, the accuracy of the test can decrease. But the real point of these rapid tests is to quickly diagnose people at the highest risk of spreading COVID and get them into isolation, which they do well. 

What’s Next?

Rapid tests can get people their results quickly. If you were exposed to someone with COVID-19 or have symptoms of COVID-19, they will be accurate. Regardless of whether you can get a test, the safest plan is to quarantine for 14 day immediately after you are exposed to a COVID-19 positive person. And don’t wait to start personal contact tracing!

 

Last update: September 10, 2020 4:23 pm ET

Science review: ERS, JAB