Abstract
Following the Swiss Federal Office of Public Health (FOPH) authorization of the rapid antigen test (RAT), we implemented the use of the RAT in the emergency ward of our university hospital for patients’ cohorting. RAT triaging in association with RT-PCR allowed us to promptly isolate positive patients and save resources. Among 532 patients, overall sensitivities were 48.3% for Exdia and 41.2% for Standard Q®, PanbioTM and BD Veritor™. All RATs exhibited specificity above 99%. Sensitivity increased to 74.6%, 66.2%, 66.2% and 64.8% for Exdia, Standard Q®, PanbioTM and BD Veritor™, respectively, for viral loads above 105 copies/mL, to 100%, 97.8%, 96.6% and 95.6% for viral loads above 106 copies/mL and 100% for viral loads above 107 copies/mL. Sensitivity was significantly higher for patients with symptoms onset within four days (74.3%, 69.2%, 69.2% and 64%, respectively) versus patients with the evolution of symptoms longer than four days (36.8%, 21.1%, 21.1% and 23.7%, respectively). Among COVID-19 asymptomatic patients, sensitivity was 33%. All Immunoglobulin-A-positive patients resulted negative for RAT. The RAT might represent a useful resource in selected clinical settings as a complementary tool in RT-PCR for rapid patient triaging, but the lower sensitivity, especially in late presenters and COVID-19 asymptomatic subjects, must be taken into account.
Highlights
From November 7 to December 16, all patients presenting at the emergency department, with or without COVID-19 symptoms, were screened with rapid antigen test (RAT) at the laboratory built inside the emergency ward
The Standard Q® antigen test from Roche was used as a reference; only its result was available to patients and clinicians
From November 7 to December 16, all patients presenting at the emergency depart5 of 13 ment, with or without COVID-19 symptoms, were screened with RAT at the laboratory built inside the emergency ward
Summary
Since the beginning and throughout the COVID-19 pandemic [1,2], SARS-CoV-2 has forced laboratories to constantly increase the number of tests performed and shorten the time to results. SARS-CoV-2-positive rates worldwide, with about 1800 positive new cases per 100,000 inhabitants in 14 days [3]. During this time, Lausanne University Hospital (CHUV), a 4.0/). Microorganisms 2021, 9, 798 tertiary-care center of 1500 beds, experienced a massive influx of patients, rapidly exceeding its overall capacity, with up to 280 patients hospitalized for COVID-19, including. 56 patients requiring intensive-care-unit (ICU) management (largely above the 30 ICU beds generally available). Among patients consulting the emergency department, approximately 50%
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