1. Performance of antigen testing for diagnosis of COVID-19: a direct comparison of a lateral flow device to nucleic acid amplification based tests
- Author
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Christina C. Bartenschlager, Lukas Schuierer, Christine Dhillon, Ramona Frey, Marie Freitag, Margit Heier, Stephan Zellmer, Christoph Römmele, Elisabeth Kling, Markus Wehler, Alanna Ebigbo, Reinhard Hoffmann, Maria Kahn, Helmut Messmann, Christian Denzel, and Selin Temizel
- Subjects
medicine.medical_specialty ,Point-of-care testing ,Infectious and parasitic diseases ,RC109-216 ,COVID-19 testing ,Sensitivity and Specificity ,Gastroenterology ,Asymptomatic ,Medical microbiology ,Antigen ,(3–10): SARS-CoV-2 ,Internal medicine ,medicine ,Humans ,ddc:610 ,SARS-COV-2 antigen testing ,Retrospective Studies ,SARS-CoV-2 ,business.industry ,Research ,COVID-19 ,Retrospective cohort study ,Gold standard (test) ,Nucleic acid amplification technique ,Infectious Diseases ,Parasitology ,RNA, Viral ,medicine.symptom ,business ,Nucleic Acid Amplification Techniques - Abstract
Objectives The gold standard for diagnosing an infection with SARS-CoV-2 is detection of viral RNA by nucleic acid amplification techniques. Test capacities, however, are limited. Therefore, numerous easy-to-use rapid antigen tests based on lateral flow technology have been developed. Manufacturer-reported performance data seem convincing, but real-world data are missing. Methods We retrospectively analysed all prospectively collected antigen tests results performed between 23.06.2020 and 26.11.2020, generated by non-laboratory personnel at the point-of-care from oro- or nasopharyngeal swab samples at the University Hospital Augsburg and compared them to concomitantly (within 24 h.) generated results from molecular tests. Results For a total of 3630 antigen tests, 3110 NAAT results were available. Overall, sensitivity, specificity, NPV and PPV of antigen testing were 59.4%, 99.0%, 98.7% and 64.8%, respectively. Sensitivity and PPV were lower in asymptomatic patients (47.6% and 44.4%, respectively) and only slightly higher in patients with clinical symptoms (66.7% and 85.0%, respectively). Some samples with very low Ct-values (minimum Ct 13) were not detected by antigen testing. 31 false positive results occurred. ROC curve analysis showed that reducing the COI cut-off from 1, as suggested by the manufacturer, to 0.9 is optimal, albeit with an AUC of only 0.66. Conclusion In real life, performance of lateral-flow-based antigen tests are well below the manufacturer's specifications, irrespective of patient’s symptoms. Their use for detection of individual patients infected with SARS-CoV2 should be discouraged. This does not preclude their usefulness in large-scale screening programs to reduce transmission events on a population-wide scale.
- Published
- 2021