Over 20 states aren’t including results from a type of rapid COVID-19 test in their overall case numbers, according to a survey by Kaiser Health News (KHN). The federal government is sending millions of these types of tests all around the country in an effort to keep up with the pandemic. If states don’t release the results from those tests through their public health departments, it creates a blind spot in the overall data.
The tests, called antigen tests, work by detecting a small protein on the surface of the coronavirus. They tend work much faster than the tests that look for the virus itself, called PCR tests, although they can be less accurate.
According to the KHN survey, 21 states and the District of Columbia don’t report all of their antigen test results. Fifteen states and DC don’t count positive antigen test results as confirmed cases, and nearly half of the 48 states that responded to the survey said that their antigen test results are probably underreported.