Current Knowledge
Rapid antigen tests are a form of diagnostic test used to detect the presence of SARS-CoV-2 antigens in a sample from the respiratory tract of a person with suspected COVID-19 infection. Designed to produce results quickly, often within 15-30 minutes, two of the major advantages of rapid antigen tests are their speed and ease of use. They do not require specialized laboratory equipment or trained personnel and can be performed in a variety of settings, including at home. Rapid antigen tests are also relatively inexpensive compared to other diagnostic tests.
However, rapid antigen tests have some limitations. They are not as accurate as NAAT/PCR tests, particularly in detecting asymptomatic cases, and have a higher rate of false negatives. Therefore, negative results from rapid antigen tests should be confirmed with an NAAT/PCR test if there is a high suspicion of COVID-19 infection.
Background
The use of rapid antigen tests has become increasingly widespread in the management of COVID-19, particularly in situations where timely diagnosis is important. CDC researchers estimate that 1 in 3 U.S. households used at least one at-home rapid testing kit ordered through COVIDTests.gov from January – May 2022. Rapid tests are often used in screening programs for nursing homes, schools, workplaces and other settings to identify infected individuals quickly and prevent further spread of the virus.
Guidelines
IDSA guidelines recommend that rapid antigen tests be used as a screening tool for asymptomatic individuals and in settings with a high prevalence of COVID-19. They also recommend that negative results be confirmed with a PCR test in certain situations, such as in individuals with symptoms or known exposure to the virus.
NIH guidelines recommend that rapid antigen tests be used as an initial diagnostic tool in individuals with symptoms consistent with COVID-19, in settings where PCR testing is not immediately available or results may be delayed and in situations where there is a high prevalence of COVID-19.