Comparison of SARS-CoV-2 Antigen Tests in Asymptomatic Testing of Passengers at German Airports under Time Constraints: Application of Three Different Antigen Test Formats

Laura Pradas,Andreas Heuer,Volkmar Weckesser,Leon Wille,Stephan Schaefer,Robert Knote,Jennifer Hannen,Peter Kleinow,Christian Schölz,Jörg Hartkamp,Nikenza Viceconte,Peter Bauer,Axel Schubert

doi:10.3390/covid1030046

Laura Pradas, Andreas Heuer + Show 11 more

Open Access

https://doi.org/10.3390/covid1030046

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Abstract

People infected asymptomatically with SARS-CoV-2 can spread the virus very efficiently. To break infection chains, massive testing efforts are underway. While the value of RT-PCR in asymptomatic patients is established, point-of-care (POC) antigen tests against SARS-CoV-2 are considered inferior to RT-PCR in terms of sensitivity and specificity but have demonstrated utility, mostly in symptomatic patients. We compared the performance of three different antigen tests with colorimetric (Roche), fluorometric (Quidel Sofia 2), and instrument-based chemiluminescent (Fujirebio Lumipulse® G) readout. Sensitivities for Roche, Quidel, and Fujirebio were 62.5%, 90.9%, 97.5% (≤ct 26); 43.8%, 90.9%, 95.1% (≤ct 30); and 4.3%, 0.0%, 57.6% (˃ct 30), respectively. The two assays with increased sensitivity were employed to screen > 35,000 passengers at German airports under time constraints. Under real-world conditions, the rate of false positives was low: 0.15% (Quidel) and 0.06% for the instrument based Fujirebio assay. Our study exemplifies that antigen tests with enhanced detection methods have an acceptable sensitivity of >90% in samples containing SARS-CoV-2 RNA that are considered to be infectious. Therefore, our results support the view of the WHO that discourages the use of antigen assays with a sensitivity of “only” 80% for screening travelers.

Highlights

Since the discovery of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV2), RT-PCR-based diagnostic testing has been considered the gold standard due to its high sensitivity and specificity [1]
Due to globally rising numbers of infections and in order to meet the demands of testing and reduce transmission, SARS-CoV-2 antigen-detecting diagnostic tests have been developed in order to complement PCR-based testing [2,3]
While tens of thousands of samples have been described in point-of-care antigen testing approaches in symptomatic COVID-19 patients, the performance of POC antigen tests and laboratory instrument-based tests as compared with RT-PCR as a gold standard in asymptomatic individuals is scarce [5,13,14]

Summary

Introduction

Since the discovery of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV2), RT-PCR-based diagnostic testing has been considered the gold standard due to its high sensitivity and specificity [1]. Due to globally rising numbers of infections and in order to meet the demands of testing and reduce transmission, SARS-CoV-2 antigen-detecting diagnostic tests have been developed in order to complement PCR-based testing [2,3]. The performance of such test formats in mostly asymptomatic non-COVID-19 individuals, for example travelers, is not so clear because virus load in asymptomatic individuals is significantly lower and test numbers are higher [7]. In contrast to symptomatic patients, asymptomatic COVID-19 cases do not develop symptoms over the duration of infection, but both are crucial drivers of transmission [8]. Most of them do not know about their infection but contribute to a large proportion of new cases and transmissions [9,10]

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