Utility of the FebriDx point‐of‐care test for rapid triage and identification of possible coronavirus disease 2019 (COVID‐19)
Nawazish Karim, Muhammad Zubair Ashraf, Muhammad Naeem, Tahir Anwar, Hnin Aung, Srikumar Mallik, Eleni Avraam, Sidra Kiran, Sareesh Bandapaati, Faisal Khan, Georgios Tsaknis, Raja Reddy
Abstract
OBJECTIVES: The Coronavirus disease 2019 (COVID-19) pandemic is straining healthcare resources. Molecular testing turnaround time precludes having results at the point-of-care (POC) thereby exposing COVID-19/Non-COVID-19 patients while awaiting diagnosis. We evaluated the utility of a triage strategy including FebriDx, a 10-minute POC finger-stick blood test that differentiates viral from bacterial acute respiratory infection through detection of Myxovirus-resistance protein A (MxA) and C-reactive protein (CRP), to rapidly isolate viral cases requiring confirmatory testing. METHODS: This observational, prospective, single-center study enrolled patients presenting to/within an acute care hospital in England with suspected COVID-19 between March and April 2020. Immunocompetent patients ≥16 years requiring hospitalisation with pneumonia or acute respiratory distress syndrome or influenza-like illness (fever and ≥1 respiratory symptom within 7 days of enrolment, or inpatients with new respiratory symptoms, fever of unknown cause or pre-existing respiratory condition worsening). The primary endpoint was diagnostic performance of FebriDx to identify COVID-19 as a viral infection; secondary endpoint was SARS-CoV-2 molecular test diagnostic performance compared with the reference standard COVID-19 Case Definition (molecular or antibody detection of SARS-CoV-2). RESULTS: Valid results were available for 47 patients. By reference standard, 35 had viral infections (34/35 COVID-19; 1/35 non-COVID-19; overall FebriDx viral sensitivity 97.1% (95%CI 83.3-99.9)). Of the COVID-19 cases, 34/34 were FebriDx viral positive (sensitivity 100%; 95%CI 87.4-100); 29/34 had an initial SARS-CoV-2 positive molecular test (sensitivity 85.3%; 95%CI 68.2-94.5). FebriDx was viral negative when the diagnosis was not COVID-19 and SARS-Cov-2 molecular test was negative (negative predictive value (NPV) 100% (13/13; 95%CI 71.7-100)) exceeding initial SARS-CoV-2 molecular test NPV 72.2% (13/19; 95%CI 46.4-89.3). The diagnostic specificity of FebriDx and initial SARS-CoV-2 molecular test was 100% (13/13; 95%CI 70-100 and 13/13; 95%CI 85.4-100, respectively). CONCLUSIONS: FebriDx could be deployed as part of a reliable triage strategy for identifying symptomatic cases as possible COVID-19 in the pandemic.