COVID-19

Optimizing Use of Ag RDTs in national COVID-19 testing strategies and C19RM Applications

18 June 2021

Effective testing for SARS-COV-2 remains a vital part of a national strategy to suppress virus transmission and save lives. Boosting testing through higher and more effective Ag RDT use as part of this strategy is strongly encouraged.   

Following the update we sent you on 20 May on scaling up COVID-19 diagnostics using Ag RDTs, we would like to share additional information that WHO has recently circulated to partners and WHO Regional Offices:

• Ag RDT testing can be carried out by trained individuals, including community health workers. WHO recommends the use of Ag RDTs, which can be used outside of health facility and laboratory settings, including in communities. Ag RDTs should be administered by trained individuals, that can include community health care workers and many others, following national laws and regulations supporting task-shifting/task-sharing and decentralization of health services to maximize access and facilitate infection prevention and control. A training package is available on the WHO website, with versions in English, French, Spanish, Russian, and Portuguese.
• Ag RDT results do not require routine confirmation by PCR, if testing is carried out by trained individuals according to manufacturer’s instructions. In settings with limited transmission or individuals with low risk of infection being tested, such as asymptomatic individuals without exposure to a known case, there is an increased likelihood that some infections will be missed due to low sensitivity. This is likely to result in many positive RDT results that are false-positives (low positive predictive value). In such settings and when test results are in doubt, confirmation by repeat testing – ideally by PCR – is recommended.
• For more information on the different types of tests available and use cases for Ag RDT see these WHO Infographics: Diagnostic Testing for SARS-CoV-2 infectionand Use of antigen-detection rapid diagnostic testing. 

We strongly encourage C19RM applicants to consider the above information when developing their C19RM funding requests, in order to optimize access to high quality, cost-effective (US$3 per Ag RDT vs. US$20 per XPert SARS CoV-2 cartridge), and decentralized COVID-19 testing within national responses.  

WHO is updating its Ag RDT guidance as well as preparing interim guidance on Recommendations for National SARS-CoV-2 Testing Strategies and Diagnostic Capacities. The new guidance is expected in the coming weeks.