Transmission electron micrograph of SARS-CoV-2 virus particles isolated from a patient. Image acquisition and color enhancement at the NIAID Integrated Research Facility (IRF) in Fort Detrick, Maryland. Image Credit: NIAID
A prospective study found that serial antigen testing could be an effective strategy to aid infection control in nursing homes with SARS-CoV-2 outbreaks. While the authors are less sensitive than real-time reverse transcription polymerase chain reaction (RT-PCR) diagnostic tests, they say antigen tests work well when it counts – when someone is infectious and at risk of getting the virus to spread. The results are published in the Annals of Internal Medicine.
Serial, facility-wide testing for SARS-CoV-2 can help identify cases in outbreak environments and enable rapid implementation of transmission-based precautions and infection prevention and control strategies. RT-PCR tests performed in a laboratory are the most sensitive, but their increased turnaround time can delay the implementation of quarantine and isolation. Antigen testing is easy to perform and provides results in minutes that enable quick action. However, there is a lack of performance data, especially for asymptomatic individuals.
Researchers from the Centers for Disease Control and Prevention (CDC) examined 532 samples from 234 available residents and employees of a nursing home with a SARS-CoV-2 outbreak to assess the performance of antigen tests when used during an emerging outbreak. Three copies were collected three times over a period of 13 days from all residents and employees. Trained laboratory scientists tested one swab on site with a rapid antigen test and the other was sent to the CDC for RT-PCR and virus culture reference test. The researchers found that the overall antigen test was less sensitive than RT-PCR, but performed well in identifying early infections and samples with replication-competent virus (i.e., culture positive). In addition, a consensus test analysis of people with a positive result and more than one test found that repeated testing, even in asymptomatic patients, gave a similar positive agreement for antigen testing compared to RT-PCR. According to the authors, these data suggest that early and frequent antigen testing during a SARS-CoV-2 outbreak may be an effective strategy for identifying infectious individuals with the greatest potential to transmit the virus.
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Provided by the American College of Physicians
Quote: Serial Antigen Testing May Be an Effective Strategy to Control Infection During a SARS-CoV-2 Outbreak in the Nursing Home (2721, April 27), posted on April 27, 2021 from https://medicalxpress.com/news/2021- 04-serial-antigen was retrieved -effective-strategy-infection.html
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