What you need to know about at-home rapid tests and their results

At-home rapid tests have proven to be a powerful weapon in the country's battle against the coronavirus and its latest variants, but the surge of the omicron variant has left U.S. consumers to contend with concerns about access, efficacy and rising costs among the numerous options on the market.

Health experts say rapid tests remain a useful tool as the country braces for the latest surge in cases, as long as they can be obtained and are considered in the right context. The tests sacrifice some accuracy for speedy results, but they can be an aid for making decisions and knowing when to get additional treatment.

The most accurate tests available are polymerase chain reaction tests, or PCR tests, which detect tiny snippets of the virus’s genetic material. Because the tests require specialized lab equipment, people can wait for days to get their results, particularly when there are surges, as demand grows and logjams are created.

Rapid tests, on the other hand, detect molecules that are found on the virus’s surface, called antigens. They’re not as accurate, but they can be run at home and provide results in as little as 15 minutes.

The tests themselves are most accurate when a person has symptoms, studies suggest. While they are able to detect asymptomatic cases, there’s a greater likelihood for false negatives. Most experts agree that people get positive antigen results when they’re most contagious.

If the course of an infection resembles a bell curve on a chart, a PCR test is good at detecting the infection all the way through. A rapid antigen test is best at detecting within the hump of that curve, when a person is most infectious and poses the biggest risk to others.  ...