The U.S. Food and Drug Administration said today (November 3) it is alerting clinical laboratory staff and healthcare providers that false positive results can occur with COVID-19 antigen tests.
The decision was made following reports of false positive results associated with the tests used in nursing homes.
The U.S. agency said false positive results may occur when users do not follow the instructions for the use of antigen tests for rapid detection of SARS-CoV-2.
Antigen tests detect proteins on the surface of the virus. They require an uncomfortable nasal or throat swab, and can produce results more quickly than molecular tests – which detect genetic material in the virus – but are considered less accurate.
COUNTRIES TURNING TO LESS ACCURATE TESTS
Countries straining to contain a second wave of COVID-19 are turning to faster, cheaper but less accurate tests to avoid the delays and shortages that have plagued efforts to diagnose and trace those infected quickly.
The FDA issued the first emergency use authorisation (EUA) for a COVID-19 antigen test in May.
The U.S. government has signed agreements with several companies including Becton Dickinson and Quidel Corp to supply antigen tests to U.S. nursing homes in an attempt to identify outbreaks faster and stem the tide of the virus.
In September, Becton Dickinson, which is supplying 750,000 of its SARS-CoV-2 antigen test to the U.S. government, said it is investigating reports from U.S. nursing homes that its rapid coronavirus testing equipment is producing false-positive results.