2023. A Prospective, Multi-Center U.S. Clinical Trial to Determine Accuracy of FebriDx Point-of-Care Testing for Acute Upper Respiratory Infections with and Without a Confirmed Fever

Abstract

BackgroundFebriDx is a 10-minute disposable point-of-care test designed to identify clinically significant systemic host immune responses and aid in the differentiation of viral and bacterial respiratory infection by simultaneously detecting C-reactive protein (CRP) and myxovirus resistance protein A (MxA) from a fingerstick blood sample.MethodsA prospective, multicenter, cross-sectional study of primarily adults with acute upper respiratory tract infections (URIs), with and without a confirmed fever at the time of enrollment, was performed to evaluate the diagnostic accuracy of FebriDx to identify clinically significant bacterial infection with host response and acute pathogenic viral infection. URI was defined as rhinosinusitis, pharyngitis, nonspecific URI, and bronchitis and the reference method consisted of an algorithm that included throat bacterial cell culture, respiratory PCR panels for viral and atypical pathogens, procalcitonin, white blood cell count, and bandemia. The algorithm also utilized the Centor criteria and allowed for physician over-ride.ResultsAmong 220 patients enrolled, 100% reported fever ≥100.5 within the last 72 hours while 55% (121/220) had a confirmed fever at the time of enrollment. Of the total enrolled patients, 15% (34/220) were classified as bacterial, 56% (124/220) were classified as viral, and 28% (62/220) negative by the reference standard. Sample Size (n) Confirmation of Fever Diagnosis Sensitivit % and [95% CI] Specificity % and [95% CI] Positive Predictive Value (PPV)% and [95% CI] Negative Predictive Value (NPV)% and [95% CI] 220Reported within last3 daysBacterial 85 (29/34) [69-95] 93 (183/196) [89-96] 69 (29/42 ) [56-79] 97 (183/188) [94-99]Viral 90 (111/124) [83-94] 76 (73/96) [66-84] 83 (111/134) [77-87] 85 (73/86) [77-90]121Exhibited on enrollmentBacterial 95 (19/20) [77-100] 94 (95/101) [88-98] 76 (19/25) [59-87] 99 95/96) [93-100]Viral 90 (72/80) [81-96] 78 (32/41) [62-89] 89 (72/81) [82-93] 80 (32/40) [67-89]ConclusionWhen comparing clinical accuracy of diagnostic tests, performance values should be determined in febrile patients. FebriDx’s 97–99% NPV may help to identify clinically significant bacterial URI’s and supports outpatient antibiotic decisions.Disclosures R. Sambursky, Rapid Pathogen Screening, Inc.: Board Member, Employee and Shareholder, Salary.