However, a positive result is more likely to be a false positive when the prevalence of the virus is low. Rapid antigen tests generate relatively few false positives. When implementing any kind of testing regime, it is important to consider the impact of false positives. President Biden could accomplish this with a simple Executive Order, increasing competition among manufacturers and flooding the market with inexpensive, high-quality rapid tests.
But as discussed in this article, rapid tests are the “public health gold standard” and should therefore be regulated as a Public Health Good. To be approved, the rapid tests must demonstrate that they are nearly as sensitive as the gold standard PCR. process intended for high-tech medical devices. Widespread accessibility to rapid tests in the US is presently hampered by a cumbersome F.D.A. The Biden administration’s announcement to use the Defense Production Act to increase production of rapid tests and invest $1 billion in rapid testing is a welcome change but there is an additional step they could take to encourage routine rapid testing. This ability to rapidly detect the virus in those most likely to transmit the virus makes rapid tests the “public health gold standard”. This is particularly critical with many returning to schools, college campuses, offices, and the resumption of live events.
Given their rapid results, lateral flow tests are also better suited than PCR tests for identifying and containing the pre-symptomatic spread of the virus. But the two tests work in different ways, lateral flow tests detect material from the surface proteins of the virus and are very likely to give a positive result when someone is infectious whereas PCR tests detect the virus' genetic material, which can be present for weeks after a person is no longer infectious. Validation studies for lateral flow tests have mostly focused on comparing sensitivity, specificity, and predictive values to PCR tests. It has been reported that in Europe some who live with high risk or immunocompromised individuals, even keep a stash of rapid tests by the front door and ask visitors to test themselves before entering their home. The tests give a quick result using a device similar to a pregnancy test. However, mass antigen rapid lateral flow tests have recently been rolled out in several countries for regularly testing asymptomatic individuals as part of public health policy. Covid-19 testing has traditionally focused on diagnosing symptomatic individuals using reverse PCR tests.