A rapid host–protein test for differentiating bacterial from viral infection: Apollo diagnostic accuracy study

Objectives To determine the diagnostic accuracy of a rapid host‐protein test for differentiating bacterial from viral infections in patients who presented to the emergency department (ED) or urgent care center (UCC). Methods This was a prospective multicenter, blinded study. MeMed BV (MMBV), a test based on tumor necrosis factor‐related apoptosis‐inducing ligand (TRAIL), interferon gamma‐inducible protein‐10 (IP‐10), and C‐reactive protein (CRP), was measured using a rapid measurement platform. Patients were enrolled from 9 EDs and 3 UCCs in the United States and Israel. Patients >3 months of age presenting with fever and clinical suspicion of acute infection were considered eligible. MMBV results were not provided to the treating clinician. MMBV results (bacterial/viral/equivocal) were compared against a reference standard method for classification of infection etiology determined by expert panel adjudication. Experts were blinded to MMBV results. They were provided with comprehensive patient data, including laboratory, microbiological, radiological and follow‐up. Results Of 563 adults and children enrolled, 476 comprised the study population (314 adults, 162 children). The predominant clinical syndrome was respiratory tract infection (60.5% upper, 11.3% lower). MMBV demonstrated sensitivity of 90.0% (95% confidence interval [CI]: 80.3–99.7), specificity of 92.8% (90.0%–95.5%), and negative predictive value of 98.8% (96.8%–99.6%) for bacterial infections. Only 7.2% of cases yielded equivocal MMBV scores. Area under the curve for MMBV was 0.95 (0.90–0.99). Conclusions MMBV had a high sensitivity and specificity relative to reference standard for differentiating bacterial from viral infections. Future implementation of MMBV for patients with suspected acute infections could potentially aid with appropriate antibiotic decision‐making.