Performance characteristics of five antigen-detecting rapid diagnostic test (Ag-RDT) for SARS-CoV-2 asymptomatic infection: a head-to-head benchmark comparison. Issue 6 (June 2021) - Baro, Bàrbara
Highlights: Ag-RDTs sensitivity for SARS-CoV-2 in unexposed asymptomatic individuals was 29–52%. Sensitivity increased to 70–87% for specimens with high risk of viral transmission. Four Ag-RDTs (Abbott, Siemens, Roche, and Surescreen) showed specificity >96%. In mass-screening campaigns, positive Ag-RDT results should be confirmed by PCR. Summary: Background: Mass testing for early identification and isolation of infectious COVID-19 individuals is efficacious for reducing disease spread. Antigen-detecting rapid diagnostic tests (Ag-RDT) may be suitable for testing strategies; however, benchmark comparisons are scarce. Methods: We used 286 nasopharyngeal specimens from unexposed asymptomatic individuals collected between December 2020 and January 2021 to assess five Ag-RDTs marketed by Abbott, Siemens, Roche Diagnostics, Lepu Medical, and Surescreen. Results: For the overall sample, the performance parameters of Ag-RDTs were as follows: Abbott assay, sensitivity 38.6% (95%CI 29.1–48.8) and specificity 99.5% (97–100%); Siemens, sensitivity 51.5% (41.3–61.6) and specificity 98.4% (95.3–99.6); Roche, sensitivity 43.6% (33.7–53.8) and specificity 96.2% (92.4–98.5); Lepu, sensitivity 45.5% (35.6–55.8) and specificity 89.2% (83.8–93.3%); Surescreen, sensitivity 28.8% (20.2–38.6) and specificity 97.8% (94.5–99.4%). For specimens with cycle threshold (Ct) <30 in RT-qPCR, all Ag-RDT achieved a sensitivity ≥70%. The modelled negative- and positive-predictive value for 1% prevalence were >99% and <50%, respectively. Conclusions: When screening unexposed asymptomatic individuals, two Ag-RDTs achieved sensitivity ≥80% for specimens with Ct<30 and specificity ≥96%. The estimated negative predictive value suggests the suitability of Ag-RDTs for mass screenings of SARS-CoV-2 infection in the general population.