title: Combined use of biomarkers for distinguishing between bacterial and viral etiologies in pediatric lower respiratory tract infections.
abstract: 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.
authors.affiliation: Department of Internal Medicine, Soochow University Affiliated Children's Hospital , Soochow , China.
authors.forename: Guoji
authors.initials: G
authors.lastname: Zhu
authors.forename: Jie
authors.initials: J
authors.lastname: Zhu
authors.forename: Lei
authors.initials: L
authors.lastname: Song
authors.forename: Wenzhi
authors.initials: W
authors.lastname: Cai
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
mesh_terms: D001424:Bacterial Infections / Q000175:diagnosis* / Q000382:microbiology; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis; D002116:Calcitonin / Q000097:blood; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D017463:Receptors, Complement 3b / Q000097:blood; D012141:Respiratory Tract Infections / Q000175:diagnosis* / Q000382:microbiology / Q000821:virology; D012680:Sensitivity and Specificity; D014777:Virus Diseases / Q000175:diagnosis* / Q000821:virology
chemical_list: D015415:Biomarkers; C509991:CR1 protein, human; C508600:IL6 protein, human; D015850:Interleukin-6; D017463:Receptors, Complement 3b; D002116:Calcitonin; D002097:C-Reactive Protein
keywords: Combined biomarkers; bacterial etiology; diagnostic accuracy; pediatric lower respiratory tract infections; viral etiology