Performance of a SARS-CoV-2 antigen rapid immunoassay in patients admitted to the emergency department.
Int J Infect Dis 2021;
110:135-140. [PMID:
34302961 PMCID:
PMC8295062 DOI:
10.1016/j.ijid.2021.07.043]
[Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/13/2021] [Accepted: 07/19/2021] [Indexed: 12/23/2022] Open
Abstract
Objectives
Given the ongoing pandemic emergency, there is a need to identify SARS CoV-2 infection in various community settings. Rapid antigen testing is spreading worldwide, but diagnostic accuracy is extremely variable. Our study compared a microfluidic rapid antigen test with a reference molecular assay in patients admitted to the emergency department (ED) of a general hospital from October 2020 to January 2021.
Methods
Nasopharyngeal swabs collected in patients with suspected COVID-19 and in patients with no symptoms suggesting COVID-19, but requiring hospitalization, were obtained.
Results
792 patients of median age 71 years were included. With a prevalence of 21%, the results showed: 68.7% (95% confidence interval [CI]: 60.9–75.5) sensitivity; 95.2% (95% CI: 93.1–96.7) specificity; 79.2% (95% CI: 71.4–85.3) positive predictive value (PPV); 91.9% (95% CI: 89.5–93.9) negative predictive value; 3.8 (95% CI: 2.7–5.3) positive likelihood ratio (LR+); and 0.09 (95% CI: 0.07–0.1) negative likelihood ratio (LR−). In the symptomatic subgroup, sensitivity increased to 81% (95% CI: 70.3–88.6) and PPV to 96.9% (95% CI: 88.5–99.5), along with an LR+ of 32 (95% CI: 8.2–125.4).
Conclusions
The new rapid antigen test showed an overall excellent diagnostic performance in a challenging situation, such as that of an ED during the COVID-19 emergency.
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