A-Z Index
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z ALL
Instagram Facebook Twitter Youtube
Reporting LAHAN Alerts
banner

Coronavirus Disease 2019

Interim Guidelines for COVID-19 Antigen Testing in Skilled Nursing Facilities


Interim Guidelines for COVID-19 Antigen Testing in Skilled Nursing Facilities

Summary of Recent Changes

5-11-22 Facilities conducting CLIA-waived point of care testing are required to report all positive SARS CoV-2 test results. Reporting of non-positive results (negative, indeterminate, etc.) is no longer required.

Print
Page
Background

Testing for SARS-CoV-2, the virus that causes COVID-19, is an important adjunct to infection control measures for preventing and controlling outbreaks in skilled nursing facilities (SNFs). The SARS-CoV-2 testing landscape is continually changing as additional tests receive an emergency use authorization (EUA) from the FDA. Technology to conduct molecular, antigen, and serology tests is now available.

Overview of Current SARS-CoV-2 Tests

Only molecular and antigen tests are recommended to diagnose current SARS-CoV-2 infection. These viral tests detect the SARS-CoV-2 virus directly either by detecting viral RNA (molecular) or viral surface proteins (antigen). Serologic tests cannot be used alone to diagnose an active SARS-CoV-2 infection, but may be used to help support or establish a diagnosis in limited circumstances.

Nucleic Acid Amplification Tests (NAATs) are currently the most accurate tests for diagnosing current COVID-19. NAATs (also known as molecular tests) detect one or more viral ribonucleic acid (RNA) genes unique to the genetic sequence of the SARS-CoV-2 virus. The NAAT procedure works by first amplifying - or making many copies of - the virus's genetic material, if any is present in a person's specimen. Amplifying those nucleic acids enables NAATs to detect very small amounts of SARS-CoV-2 RNA in a specimen, making these tests highly sensitive for diagnosing COVID-19.

NAATs can use many different methods to amplify nucleic acids and detect the virus, including reverse-transcription polymerase chain reaction (RT-PCR) and isothermal amplification (e.g., transcription mediated amplification (TMA) and loop-mediated isothermal amplification (LAMP)).

Standard laboratory-based (moderate- and high-complexity) NAATs, such as RT-PCR are considered the “gold standard” method for diagnosing current infection. In addition, there are many different NAATs authorized to be conducted in the point-of-care (POC) setting under a Clinical Laboratory Improvement Amendments (CLIA) Certificate of Waiver and some with authorization for at-home over the counter (OTC) tests.

Laboratory turn-around time for PCR test results should be less than 48 hours, however results can be delayed if laboratories are experiencing high volumes. Currently available POC NAATs' results have a TAT ranging from 15-45 minutes.

Antigen tests detect the presence of SARS-CoV-2 viral surface proteins. The main advantages of antigen tests are that results are available within 15-30 minutes, they are relatively simple to perform, and they are less expensive than RT-PCR tests. Most EUA authorized SARS-CoV-2 antigen tests are authorized as POC tests for settings with a CLIA waiver and authorized for at-home OTC tests.

Clinicians should remember that NAAT and antigen test accuracy is dependent on many factors including the test technology, specimen collection and handling, pretest clinical probability of disease, community prevalence of disease, and the specific characteristics of the assay.

See LAC DPH COVID-19 Provider Testing webpage for more information.

Using Antigen Tests in Skilled Nursing Facilities

Antigen tests can augment other testing efforts, especially in settings where RT-PCR testing capacity is limited or testing results are delayed. Rapid antigen tests should add both clinical and infection control value as they can rapidly “rule in” persons with SARS-CoV-2 infection.

Interim antigen testing guidelines from the CDC and CDPH outline a role in screening asymptomatic residents and staff in nursing homes as a strategy to rapidly detect and triage asymptomatic or pre-symptomatic cases in a vulnerable congregate setting.

This document is meant to provide clinicians working in nursing homes with guidelines to help them determine the best use of different viral tests that they can apply to the local testing conditions for each facility. 

Note: Testing for COVID-19 by using PCR is preferred. The recommendations below are intended to provide guidance on how to incorporate antigen testing when timely PCR testing is not available. See the COVID-19 Testing section of the LAC DPH Guidelines for Preventing and Managing COVID-19 in SNFs for testing requirements and resources. Facilities experiencing short term PCR testing shortages may contact LAC DPH at (213)-240-7941.

Recommended Testing Strategies
(Listed in descending order of preference)

Patient Type

Testing strategy

Response

PCR testing is easily accessible and results are available within 48 hours

All residents and Staff

Standard PCR testing per LAC DPH SNF Guidelines1

Isolate/quarantine/cohort per guidelines.

Use of POC Ag tests for response/outbreak testing; consider when PCR results not available within 48 hours2

Symptomatic resident

POC Ag test positive no additional testing

Isolate (Red Cohort).

POC Ag test negative confirm with PCR

Quarantine (Yellow Cohort) pending PCR confirmation

  • If PCR positiveRed Cohort 
  • If PCR negativeGreen Cohort with droplet precautions until after resident is clinically improved and 24 hours after resolution of fever.

Asymptomatic resident

POC Ag test positive confirm with PCR

Quarantine with transmission-based precautions appropriate for the Yellow Cohort pending confirmatory RT-PCR. Pending results of confirmatory RT-PCR testing, residents may remain in their current room. They should not be transferred to the Red Cohort or placed in another shared room with new roommates.

  • If PCR positiveRed Cohort
  • If PCR negativeGreen Cohort

POC Ag test negative confirm with PCR

Green Cohort Move to Red Cohort if PCR positive.

Symptomatic staff

POC Ag test positive no additional testing

Restrict from work. Follow return to work guidelines

POC Ag test negative confirm with PCR

Restrict from work pending PCR result

  • If PCR is positive, continue work restriction and follow return to work guidelines
  • If PCR is negative, staff may return to work when clinically improved and 24 hours after resolution of fever.

Asymptomatic staff

POC Ag test positive confirm with PCR

Restrict from work pending PCR result

  • If PCR is positive, continue work restriction and follow return to work guidelines
  • If PCR is negative, staff may return to work

POC Ag test negative Confirm with PCR

No work restriction restrict if PCR positive.

Use of POC Ag tests for Screening-Only (Not indicated for response/outbreak testing )

Asymptomatic resident

POC Ag test positive confirm with RT-PCR

Quarantine with transmission based precautions appropriate for the Yellow Cohort pending confirmatory RT-PCR. Pending results of confirmatory RT-PCR testing, residents may remain in their current room. They should not be transferred to the Red Cohort or placed in another shared room with new roommates.

  • RT-PCR positiveRed Cohort
  • RT-PCR negativeGreen Cohort

POC Ag test negative

Stay in Green Cohort. Continue serial screening.

Asymptomatic staff

POC Ag test positive confirm with RT-PCR

Restrict from work pending confirmatory RT-PCR. If restriction would result in a staff shortage, staff member may work in Red Cohort pending PCR confirmation

  • RT-PCR negative, return to work.
  • RT-PCR positive, continue work restriction and follow return to work guidelines

POC Ag test negative 

Continue serial screening.

  1. LAC DPH Guidelines for Preventing & Managing COVID-19 in Skilled Nursing Facilities.
  2. If PCR testing is insufficient to meet testing needs for all staff and residents, then prioritize residents for PCR testing.
Reporting Results

All Facilities must have a CLIA Certificate of Waiver to use POC devices*. Facilities must report all positive POC test results to LAC DPH. This data must be reported within 24 hours of test completion. For reporting guidelines, please refer to http://publichealth.lacounty.gov/acd/ncorona2019/reporting.htm#poct.

*Note: OTC tests that are self-administered (i.e., self-testing that is performed and administered by the individual) do not need a CLIA Certificate of Waiver and are not reportable. See FDA/CMS: Over the Counter (OTC) Home Testing and CLIA Applicability FAQs.

Related Resources

CDPH:

CDC:


Icon: Get Adobe Reader
Adobe Reader

Note: PDF documents on this site were created using Adobe Acrobat 5.0 or later. Document functionality may be reduced if you are using an earlier version (4.x or less). Get the latest version of Adobe Acrobat.



Public Health has made reasonable efforts to provide accurate translation. However, no computerized translation is perfect and is not intended to replace traditional translation methods. If questions arise concerning the accuracy of the information, please refer to the English edition of the website, which is the official version.

Los Angeles County Seal: Enriching lives through effective and caring services