This doc gives a abstract of issues to be used of SARS-CoV-2 (the virus that causes COVID-19) antigen testing in nursing houses and is meant for nursing dwelling suppliers and state and native public well being departments.
Antigen exams can be found as point-of-care (POC) diagnostics for SARS-CoV-2. They’ve a fast turnaround time, which is vital to the identification of SARS-CoV-2 an infection and fast implementation of an infection prevention and management methods. These exams can increase different testing efforts, particularly in settings the place RT-PCR testing capability is proscribed or testing outcomes are delayed (e.g., >48 hours). Usually, these POC antigen exams have a decrease sensitivity, however comparable specificity, for detecting SARS-CoV-2 in comparison with reverse-transcriptase polymerase chain response (RT-PCR) exams.
This doc pertains to antigen exams which have been granted a US Meals and Drug Administration’s Emergency Use Authorization (FDA EUA) to detect SARS-CoV-2. The primary two SARS-CoV-2 antigen exams to obtain FDA EUA are approved for testing symptomatic individuals inside 5 days of symptom onset and there are restricted information on antigen take a look at efficiency in asymptomatic individuals. Nonetheless, given the transmission of SARS-CoV-2 from asymptomatic and presymptomatic nursing dwelling residents and healthcare personnel (HCP) with SARS-CoV-2 an infection, CDC is offering issues for using antigen exams in asymptomatic individuals throughout this public well being emergency. Services ought to concentrate on the FDA EUAexterior icon for antigen examsexterior icon and potential implications for the Medical Laboratory Enchancment Amendments (CLIA)exterior icon certificates of waiver when utilizing antigen exams in asymptomatic people and in individuals >5 days from symptom onset.
When a confirmatory molecular take a look at must be thought of
Because the sensitivity of antigen exams is usually decrease than RT-PCR, FDA EUAexterior icon recommends that damaging POC antigen exams be thought of presumptive. Medical employees in nursing houses ought to contemplate when confirmatory RT-PCR testing is likely to be wanted prior to creating scientific selections, cohorting residents, or excluding HCP from work. When decoding the outcomes of antigen exams, take a look at traits and likelihood of an infection must be thought of.
- Check sensitivity may range between antigen testing platforms. Services ought to concentrate on which platform is getting used and the sensitivity of the take a look at for the affected person inhabitants to be examined. For instance, the primary two antigen exams which have acquired FDA EUAsexterior icon vary in sensitivity from 84% to 97% when used inside 5 days of symptom onset.
- Elements that improve the likelihood of an infection embody the presence of signs within the particular person being examined, current publicity to somebody recognized with COVID-19, and whether or not testing is being performed in a nursing dwelling with an outbreak or inside a high-prevalence group. These components inform the choice of whether or not confirmatory testing by RT-PCR is indicated following an antigen take a look at.
If a confirmatory RT-PCR take a look at is carried out inside 48 hours, people must be assumed infectious till the confirmatory take a look at outcomes are accomplished. As an illustration, if a symptomatic resident exams presumptive damaging on antigen take a look at and a RT-PCR is carried out, the resident ought to stay in Transmission-Based mostly Precautions till the RT-PCR take a look at outcomes. If an asymptomatic HCP working in a nursing dwelling with out an outbreak and in a county with low group prevalence exams antigen optimistic, they need to be excluded from work till a damaging RT-PCR take a look at is offered.
Reporting necessities for SARS-CoV-2 exams
Each COVID-19 testing website is required to report to the suitable state or native public well being division each diagnostic and screening take a look at carried out to detect SARS-CoV-2 or to diagnose a attainable case of COVID-19. POC testing could also be carried out with a Medical Laboratory Enchancment Amendments (CLIA)exterior icon certificates of waiver, however reporting of take a look at outcomes to state or native public well being departments are mandated by the Coronavirus Help, Reduction, and Financial Safety (CARES) Act.
CMS-certified long-term care amenities are required by the Division of Well being and Human Companiespdf iconexterior icon (HHS) to make use of the Nationwide Healthcare Security Community (NHSN) to report SARS-CoV-2 point-of-care antigen take a look at information, and different on-site COVID-19 laboratory testing information, to applicable federal and state well being authorities.
Makes use of of antigen testing in nursing houses
This doc guides the interpretation of outcomes when antigen exams are used within the following circumstances:
- Testing of symptomatic residents and HCP,
- Testing of asymptomatic residents and HCP in amenities as a part of an COVID-19 outbreak response, and
- Testing of asymptomatic HCP in amenities with no COVID-19 outbreak as required by CMS suggestions.
Testing in different circumstances are prone to happen, resembling testing asymptomatic residents and HCP who had been uncovered to individuals with COVID-19 outdoors of the nursing dwelling (e.g., current hospitalization or outpatient companies) or by means of different screening actions. The rules described right here can be utilized to information the interpretation of antigen take a look at leads to these conditions.
Antigen exams ought to not be utilized to find out the period of Transmission-Based mostly Precautions nor when HCP can return to work. Check-based methods usually are not typically really useful to find out period of transmission-based precautions, nor to find out when HCP could return to work. If used, test-based methods ought to rely solely on RT-PCR.
Issues for decoding antigen take a look at leads to nursing houses
Testing of symptomatic residents or HCP
- If an antigen take a look at is optimistic, no confirmatory take a look at is critical.
- If an antigen take a look at is presumptive damaging, carry out RT-PCR instantly (e.g., inside 48 hours).
- Symptomatic residents and HCP must be stored in transmission-based precautions or excluded from work till RT-PCR outcomes return.
- Some antigen platforms have greater sensitivity when testing people inside 5 days of symptom onset. Medical discretion must be utilized to find out if people who take a look at damaging on such platforms must be retested with RT-PCR.
- Be aware: if a person has recovered from SARS-CoV-2 an infection previously 3 months and develops new signs suggestive of COVID-19, different diagnoses must be thought of previous to retesting for SARS-CoV-2.
Testing of asymptomatic residents or HCP in nursing houses as a part of an outbreak response*
- If an antigen take a look at is optimistic, no confirmatory take a look at is critical.
- Residents must be positioned in transmission-based precautions, and HCP must be excluded from work.
- If an antigen take a look at is presumptive damaging, residents must be positioned in applicable precautions for amenities with an outbreak. HCP must be allowed to proceed to work with continued symptom monitoring. The power ought to proceed serial viral testing (antigen or RT-PCR) each 3-7 days till no new instances are recognized for a 14-day interval.
- Be aware: asymptomatic people who’ve recovered from SARS-CoV-2 an infection previously 3 months and stay or work in a nursing dwelling performing facility-wide testing shouldn’t be examined for SARS-CoV-2.
Testing of asymptomatic HCP in nursing houses with out an outbreak per CMS suggestions
CMS recommendsexterior icon preliminary testing of all HCP as a part of the nursing dwelling reopening course of and serial testing of HCP at an interval based mostly on native incidence of COVID-19.
- If an antigen take a look at is optimistic, carry out confirmatory RT-PCR take a look at inside 48 hours of the antigen take a look at, particularly in counties with low prevalence. If confirmatory take a look at is carried out, HCP must be excluded from work till confirmatory take a look at outcomes are accomplished.
- If the confirmatory take a look at is optimistic, then exclude the HCP from work and provoke an outbreak response together with facility-wide testing of all residents and HCP.
- If the confirmatory take a look at is damaging, talk about outcomes with the native public well being division to find out find out how to interpret the discordant outcomes and subsequent steps. The incidence of SARS-CoV-2 an infection in the local people will help interpret the probability of a false optimistic antigen take a look at. The time between antigen take a look at and RT-PCR take a look at must also be thought of. If RT-PCR is carried out >48 hours after an antigen take a look at, it’s attainable that the viral dynamics have modified through the time between antigen and RT-PCR and testing. Subsequently, the antigen take a look at could point out a real an infection even when the RT-PCR is damaging.
- If an antigen take a look at is presumptive damaging, enable HCP to proceed to work. The HCP ought to proceed to watch for signs, and serial testing ought to proceed per CMS suggestionsexterior icon.
- Be aware: HCP who’ve recovered from SARS-CoV-2 an infection previously 3 months and are asymptomatic ought to not be examined for SARS-CoV-2.
*A COVID-19 outbreak response in a nursing house is triggered when a resident or HCP exams optimistic for SARS-CoV-2. An index an infection in a resident ought to embody SARS-CoV-2 infections that originated within the nursing dwelling and mustn’t embody:
- Residents who had been identified to have COVID-19 on admission to the ability and had been positioned into Transmission-Based mostly Precautions.
- Residents who had been positioned into Transmission-Based mostly Precautions on admission and developed SARS-CoV-2 an infection inside the 14-day interval after admission.