The Infectious Diseases Society of America has published new guidelines for the use of SARS-CoV-2 antigen tests.
“Antigen tests have really become more and more available during the pandemic and have helped us meet the need for more universal and faster access to diagnostic tests for SARS-CoV-2” Kimberly E. Hanson, MD, MHS, associate professor of internal medicine and assistant associate professor of pathology at the University of Utah School of Medicine, said at an IDSA news briefing. “These tests can be used in a variety of contexts. “
the advice was based on a systematic review of the literature by infectious disease clinicians and clinical microbiologists, which found that clinical performance data on rapid antigenic tests that have received emergency use clearance from the FDA are “primarily limited to a single point test compared to standard nucleic acid amplification test (NAAT) as a gold standard,” the guidelines panel wrote.
“Rapid antigenic tests have high specificity and low to modest sensitivity compared to standard NAAT methods. The sensitivity of the antigen test is highly dependent on viral load, with differences observed between symptomatic versus asymptomatic individuals and the time of testing after symptom onset, ”the panel wrote.
“Based on these observations, rapid RT-PCR or laboratory NAAT remain the diagnostic methods of choice for diagnosing SARS-CoV-2 infection,” the panel continued. “However, when molecular tests are not readily available or are logistically impractical, antigen testing can help identify some people infected with SARS-CoV-2.”
The guide, which was based on evidence categorized as “very low to moderate,” includes five diagnostic recommendations:
- People with suspected symptoms of COVID-19 should be tested using NAAT (either rapid RT-PCR or laboratory NAAT) versus antigen testing.
- Asymptomatic individuals at risk of exposure to SARS-CoV-2 should be tested via a single standard NAAT (either rapid RT-PCR or laboratory NAAT) versus a single rapid antigen test.
- Asymptomatic individuals at risk of exposure to SARS-CoV-2 should receive a single standard NAAT (either rapid RT-PCR or laboratory NAAT) rather than two consecutive rapid antigen tests.
- The panel does not recommend for or against rapid single antigen testing as opposed to not testing asymptomatic people at risk of exposure to SARS-CoV-2.
- The IDSA does not advocate for or against the use of repeated rapid antigenic testing rather than not testing asymptomatic people at risk of exposure to SARS-CoV-2.
“When we reviewed the literature and made our recommendations and suggestions, this was a time when highly effective vaccines were not widely available and there was no significant coverage of the vaccinated adult population,” said Hanson . “It is likely that the role of testing will change as we see increased vaccine coverage in the population and the prevalence of infection in communities begins to decline – which we are already starting to see. “
The IDSA said the guidelines were approved by the American Society for Microbiology, the Society for Healthcare Epidemiology of America and the Pediatric Infectious Diseases Society.