25th Nov

The use of rapid antigen tests
for COVID-19 in the EU/EEA and the UK

European Control for Disease Prevention

Technical Report by European Centre for Disease Prevention and Control, Stockholm, 2020. Published 19th November 2020.

Key messages


 Rapid antigen tests can contribute to overall COVID-19 testing capacity, offering advantages in terms of
shorter turnaround times and reduced costs, especially in situations in which RT-PCR testing capacity is
limited.
 Test sensitivity for rapid antigen tests is generally lower than for RT-PCR.
 Rapid antigen tests perform best in cases with high viral load, in pre-symptomatic and early symptomatic
cases up to five days from symptom onset.
 ECDC agrees with the minimum performance requirements set by WHO at ≥80% sensitivity and ≥97%
specificity.
 ECDC recommends that EU Member States perform independent and setting-specific validations of rapid
antigen tests before their implementation.
 The use of rapid antigen tests is appropriate in high prevalence settings when a positive result is likely to
indicate true infection, as well as in low prevalence settings to rapidly identify highly infectious cases.
 Rapid antigen tests can help reduce further transmission through early detection of highly infectious
cases, enabling a rapid start of contact tracing.

Scope of this document

On 28 October 2020, a European Commission Recommendation on COVID-19 testing strategies, including the use of rapid antigen tests was published [1]. That recommendation calls for European Union/European Economic Area (EU/EEA) Member States and the United Kingdom (UK) to agree on criteria to be used for the selection of rapid antigen tests, and to share and discuss information regarding the results of validation studies. This ECDC document is intended to facilitate further discussions between Member States with the aim of reaching agreement on the criteria to be used for the selection of rapid antigen tests, as well as scenarios and settings during which it is appropriate to use rapid antigen tests. This document is also intended to support clinical validations of rapid antigen tests.

Summary

To date, testing for SARS-CoV-2 infection mostly relies on reverse transcription polymerase chain reaction (RT-PCR) performed on a nasopharyngeal specimen. This testing method remains the gold standard for detecting SARS-CoV-2 and is characterised by both high sensitivity and specificity in detecting viral ribonucleic acid (RNA).

The high volume of samples reaching the laboratories could, however, lead to a shortage of reagents and disposables and to a further increase in the turn-around time for RT-PCR tests.

Rapid antigen tests are easy to use and offer rapid results at low cost, but show lower sensitivity.

Rapid antigen tests offer multiple benefits in comparison to RT-PCR tests for the detection of SARS-CoV-2. They have been developed as both laboratory-based tests and for near-patient use (point-of-care), and results are normally generated in 10 to 30 minutes after the start of the analysis, and at low cost. Most currently available rapid antigen tests show a lower sensitivity compared to the standard RT-PCR test, while their specificity is generally reported to be high. It is important to note that rapid antigen tests may be sensitive enough to detect cases with a high viral load, i.e. pre-symptomatic and early symptomatic cases (up to five days from symptom onset; or low RT-PCR cycle threshold (Ct) value <25), which likely account for a significant proportion of transmissions.

WHO recommends rapid antigen tests that meet the minimum performance requirements of ≥80% sensitivity and ≥97% specificity, while ECDC suggests aiming to use tests with a performance closer to RT-PCR, i.e. ≥90% sensitivity and ≥97% specificity.

Rapid antigen tests should be applied in a way that compensates for the lower performance compared to RT-PCR, i.e. by including repeat testing for screening purposes and confirming test results by RT-PCR.

Besides the performance of the test, other practical and strategic aspects play a significant role in deciding if a test can be used and with which indications. Examples of these considerations are the timeliness of test results, the scalability, the simplicity of use, instrumentation availability, human and material resources, and overall logistical arrangements for sampling and testing and costs. The epidemiological situation per setting, local area, region and nationwide also affect the testing strategy. Rapid antigen tests can be used for the early detection of cases when RT-PCR testing capacities are not available and receiving timely results is critical, e.g. for contact tracing purposes. Rapid antigen tests can offer a significant advantage over RT-PCR in terms of the timeliness of results.

Due to the timeliness of results, rapid antigen tests can provide added value e.g. in the patient triage process in healthcare settings at admission. In the context of contact tracing, rapid antigen tests can allow for a faster identification of infectious contacts.

When considering whether to use rapid antigen tests, a careful analysis of the expected sample volumes, availability of resources, equipment and supplies and logistical arrangements, including the expected need for confirmatory testing and supplies for those, needs to be carried out.

Read the full report: Options for the use of rapid antigen tests for COVID-19 JD (europa.eu)

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