A rapid test is an easy-to-use diagnostic tool for identifying the presence of diseases and infections. It’s not as accurate as lab tests, but it can help people decide what actions to take. It’s important to know how a rapid test works so you can use it properly.
A lab test can detect the genetic material of a disease, while rapid antigen tests detect proteins that a virus produces. A quick result can be important for people who might not be able to get to a clinic or hospital for a few days.
At-home rapid antigen tests can be purchased at pharmacies, grocery stores and online. They are also often given out by public health agencies. People can perform a self-test by following the instructions on the package. The results are usually available in less than 30 minutes. CDC recommends that you read the manufacturer’s directions carefully before taking a self-test.
The rapid antigen test has a lower sensitivity than lab PCR tests, so it may miss some cases of infection, especially during the earliest stages of the disease when the virus isn’t producing any symptoms. It may also produce a false negative.
To reduce the chances of a false positive, people should not take the test until two days after exposure to a COVID-19 carrier or when they have been sick with flu-like symptoms for five days. Also, the test doesn’t guarantee that someone who has a negative test result does not have a COVID-19 infection, because the virus can be in the body for up to 48 hours without showing a positive result on a home-based test.
Despite their limitations, rapid antigen tests are essential tools for helping to control the spread of COVID-19 and other infectious diseases. They can be used with little training, and are cheaper than laboratory-based PCR tests. They can also be used more frequently, which is important for identifying more cases when they are most likely to happen.
Until more reliable lab-based tests are available, widespread availability of affordable and convenient rapid antigen tests is the best way to help stop the spread of infection. We shouldn’t get distracted by academic debates over sensitivity or data reporting issues that obscure the real consequence of the ongoing failure to scale up rapid testing: mounting infections, economic costs and lost lives. It’s time to rethink how we use rapid testing, and commit to bringing them to as many people as possible.