Combined use of biomarkers for distinguishing between bacterial and viral etiologies in pediatric lower respiratory tract infections

Background: In clinical practice it is often troublesome to discriminate bacterial etiologies from viral etiologies in pediatric lower respiratory tract infections (LRTIs). The aim of this study was to develop an accurate analytic method to improve diagnostic determination for bacterial and viral etiologies in pediatric LRTIs. Methods: A total of 45 children with confirmed bacterial LRTIs and 51 children with viral LRTIs were finally included after assessment of the children visiting the emergency department with a suspected infection and identification of pathogens. C-reactive protein (CRP), procalcitonin (PCT), interleukin-6 (IL-6), CD35, and CD64 were assessed and then the areas under receiver operating characteristic (ROC) curves (AUC) of PCT, IL-6, CD35, and CD64 in combination with CRP were compared to the AUC of CRP alone in all subjects. Results: The levels of CRP, PCT, IL-6, CD45, and CD64 observed in children with bacterial LRTIs were statistically higher than for viral infections. The AUC of CRP combined with CD53 (0.963, 95% confidence interval (CI) 0.921-1.002) or CD64 (0.952, 95% CI 0.907-0.998) or CD35/CD64 (0.971, 95% CI 0.932-1.004) increased compared with that of the single biomarker. Conclusions: The combined analysis improved diagnostic accuracy in children with bacterial and viral LRTIs.