Evaluation of a Novel Point-of-Care Blood Myxovirus Resistance Protein A Measurement for the Detection of Viral Infection at the Pediatric Emergency Department

Abstract

Background: Prompt differentiation of viral from bacterial infections in febrile children is pivotal in reducing antibiotic overuse. Myxovirus resistance protein A (MxA) is a promising viral biomarker. Methods: We evaluated the accuracy of a point-of-care (POC) measurement for blood MxA level compared to the reference enzyme immunoassay in 228 febrile children aged between 4 weeks and 16 years, enrolled primarily at the emergency department (ED). Furthermore, we analyzed the ability of MxA to differentiate viral from bacterial infections. Results: The mean difference between POC and reference MxA level was -76 μg/L (95% limits of agreement from -409 to 257 μg/L). Using a cutoff of 200 μg/L, POC results were uniform with the reference assay in 199 (87.3%) children. In ED-collected samples, the median POC MxA level was 571 (interquartile range [IQR], 240-955) μg/L in children with viral infections, 555 (IQR, 103-889) μg/L in children with viral-bacterial coinfections, and 25 (IQR, 25-54) μg/L in children with bacterial infections (P