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Elliott | Nursing & Rehabilitation

COVID-19 Antigen Testing in Long-Term Care Facilities

February 18, 2022

Summary of Changes

This document is intended to assist long-term care facility (LTCF) providers and state and local public health departments with interpretation of and response to results of antigen tests used to diagnose new SARS-CoV-2 infections in the following circumstances:

  • Testing of symptomatic residents and healthcare personnel (HCP),
  • Testing of asymptomatic residents and HCP in facilities as part of a SARS-CoV-2 outbreak response or following close contact with someone with SARS-CoV-2 infection, and
  • Testing of asymptomatic HCP as part of expanded screening testing in facilities without a SARS-CoV-2 outbreak.

Information on the role of testing in determining the length of work restriction  for HCP with SARS-CoV-2 infection or exposure to SARS-CoV-2 is available here: https://www.cdc.gov/coronavirus/2019-ncov/hcp/guidance-risk-assesment-hcp.html.

Information on the role of testing in mitigating staff shortages is available here: https://www.cdc.gov/coronavirus/2019-ncov/hcp/duration-isolation.html

Testing Symptomatic Residents or HCP

  • If an antigen test is positive, confirmatory testing is generally not necessary.  The symptomatic individual should be classified as having SARS-CoV-2 infection.
    • If the resident or healthcare worker is the first positive case of SARS-CoV-2 within the facility (i.e., an index case), an outbreak response might be indicated.
  • If an antigen test is negative, confirmatory testing1 with a nucleic acid amplification test (NAAT) should be performed as soon as possible (within 1 to 2 days of the antigen test).  Residents should be kept on Transmission-Based Precautions and HCP should remain excluded from work until NAAT results return.
    • If the confirmatory NAAT is negative:
      • If not in an outbreak facility and no known close contact with someone with SARS-CoV-2 infection, residents and HCP may be treated as not SARS-CoV-2 infected or exposed; further management will depend on the suspected etiology of their symptoms.
  • If the confirmatory NAAT is positive:
    • If the resident or healthcare worker is the first positive case of SARS-CoV-2 within the facility (i.e., an index case), an outbreak response might be indicated.

Some antigen platforms have higher sensitivity when testing people soon after symptom onset (e.g., within 5 days). Clinical discretion may be used when determining if people who test negative should be retested with NAAT. Confirmatory testing may not be necessary if the individual has a low likelihood of SARS-CoV-2 infection. Factors that might indicate a lower likelihood of infection include: low to moderate levels of community transmission, no known or suspected close contact with someone with SARS-CoV-2 infection, and/or the person is up to date with COVID-19 vaccination.

Asymptomatic residents or HCP in LTCF tested as part of an outbreak response or following close contact with someone with SARS-CoV-2 infection

  • If an antigen test is positive, confirmatory NAAT should generally be performed2.
    • Residents should be placed on Transmission-based Precautions in a single room or, if single rooms are not available, remain in their current room pending results of confirmatory testing. They should not be transferred to a COVID-19 unit or placed in another shared room with new roommates. HCP should be excluded from work.
  • If an antigen test is negative OR if the antigen test is positive but the confirmatory NAAT (performed within 1 to 2 days of the antigen test) is negative:
    • Residents and HCP may be treated as not SARS-CoV-2 infected; however, because of their potential exposure (in an outbreak facility or have had close contact) residents and HCP should be managed as described in current guidance for long-term care infection control and HCP return to work.
  • Note: In general, asymptomatic people who have recovered from SARS-CoV-2 infection in the past 3 months should not be tested for SARS-CoV-2.

In situations where the pre-test probability is higher (e.g., facility with a large outbreak, a person who is a close contact of someone with SARS-CoV-2 infection and is not up to date with all recommended COVID-19 vaccine doses), the antigen positive test might not require confirmation and the individual should be treated as infected with SARS-CoV-2.

Asymptomatic HCP as part of expanded screening testing in LTCF without an outbreak 

  • If an antigen test is positive, perform confirmatory NAAT as soon as possible (within 1 to 2 days of the antigen test). Asymptomatic HCP who are antigen test positive should be excluded from work but initiation of an outbreak response, including facility-wide testing, can be delayed until confirmatory test results are available.
    • If the confirmatory NAAT is negative, the antigen test should be considered a false positive and the HCP may return to work.
  • If an antigen test is negative, allow HCP to continue to work following all routine recommended infection control practices.

Note: In general, asymptomatic HCP who have recovered from SARS-CoV-2 infection in the past 3 months should not be tested for SARS-CoV-2.

For more information, please visit https://www.cdc.gov/coronavirus/2019-ncov/hcp/nursing-homes-antigen-testing.html.