Utility of the FebriDx point‐of‐care test for rapid triage and identification of possible coronavirus disease 2019 (COVID‐19)

Karim, Nawazish; Ashraf, Muhammad Zubair; Naeem, Muhammad; Anwar, Tahir; Aung, Hnin; Mallik, Srikumar; Avraam, Eleni; Kiran, Sidra; Bandapaati, Sareesh; Khan, Faisal; Tsaknis, Georgios; Reddy, Raja

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.