Use of Antigen-Detection Rapid Diagnostic Testing on COVID-19

What’s the use of antigen-detection rapid diagnostic testing on COVID-19？
WHO recommends that all suspected cases be tested for SARS-CoV-2.
Antigen-detection diagnostic testing uses upper respiratory specimen or saliva to test for SARS-CoV-2 infection by detecting viral proteins (e.g. nucleoprotein). It can be used outside of clinical and laboratory settings, including in communities.
Antigen-detection rapid diagnostic tests (Ag-RDT), with adequate performance (≥80% sensitivity and ≥97 specificity compared to a NAAT reference assay) are easy to use, can rapidly detect SARS-CoV-2 infection and do not require laboratory infrastructure.

HOW, WHEN, and WHERE to use?
Ag-RDTs are used to detect acute SARS-CoV-2 infection and are best used for situations below:

1. CASE FINDING
As a primary case-detection tool for testing all suspected cases.
It can be used to detect SARS-CoV-2 in many settings including in health facilities, testing centers, care homes, prisons, schools, communities where there is ongoing transmission.

2. CONTACT TRACING
To identify infection among asymptomatic contacts of cases.
Ag-RDTs can be used to test asymptomatic contacts of confirmed cases, even if the Ag-RDT is not specifically authorized for this use.

3. OUTBREAK INVESTIGATIONS
To confirm suspected outbreaks of COVID-19 among symptomatic individuals, especially in closed or semi-closed settings including schools, care-homes, cruise ships, prisons, work-places and dormitories, etc

4. MONITOR TRENDS
To monitor trends in disease incidence in communities, and particularly among frequently exposed workers, including health and care workers, irrespective of symptoms.

The article is quoted from WHO report.
For more information see WHO guidance September 2020 https://www.who.int/publications/i/item/antigen-detection-in-the-diagnosis-of-sars-cov-2infection-using-rapid-immunoassays.