title: Diagnostic Value of Nasopharyngeal Aspirates in Children with Lower Respiratory Tract Infections.
abstract: BACKGROUND
  The accuracy of nasopharyngeal aspirate (NPA) specimens in detecting lower respiratory pathogens remains controversial. The objective of this study was to evaluate the diagnostic accuracy of aspirates (NPAs) specimen in lower respiratory tract infections (LRTIs) in children.
  
  
  METHODS
  The prospective study was designed to collect the data of paired NPAs and bronchoalveolar lavage fluids from children with acute LRTIs from January 2013 to December 2015. All specimens were subjected to pathogen detection: bacterial detection by culture, Mycoplasma pneumoniae (Mp) detection by polymerase chain reaction assay and virus (influenza A and B viruses, parainfluenza virus [PIV] Types 1 and 3, respiratory syncytial virus, and adenovirus) detection by immunofluorescence assay. The diagnostic accuracy analysis of NPAs was stratified by age ≤3 years (n = 194) and >3 years (n = 294).
  
  
  RESULTS
  We collected paired specimens from 488 children. The positive rate of pathogen was 61.6%. For Streptococcus pneumoniae, NPA culture had the specificity of 89.9% and negative predictive value of 100% in age ≤3 years, the specificity of 97.2% and negative predictive value of 98.9% in age >3 years. For Mp, the positive predictive values of NPA was 77.4% in children ≤3 years, and 89.1% in children >3 years. For PIV III, NPA specimen had the specificity of 99.8% and negative predictive value of 96.5% in children ≤3 years. For adenovirus, NPA had the specificity of 97.8% and negative predictive value of 98.4% in age ≤3 years, the specificity of 98.9% and negative predictive value of 99.3% in age >3 years.
  
  
  CONCLUSIONS
  NPAs are less invasive diagnostic respiratory specimens, a negative NPA result is helpful in "rule out" lower airway infection; however, a positive result does not reliably "rule in" the presence of pathogens.
authors.affiliation: Department of Respiratory, Children's Hospital of Fudan University, Shanghai 201102, China.
authors.forename: Ai-Zhen
authors.initials: AZ
authors.lastname: Lu
authors.affiliation: Department of Information Management, Children's Hospital of Fudan University, Shanghai 201102; Center for Evidenced-based Medicine, Fudan University, Shanghai 200032, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Shi
authors.affiliation: Department of Respiratory, Children's Hospital of Fudan University, Shanghai 201102, China.
authors.forename: Li-Bo
authors.initials: LB
authors.lastname: Wang
authors.affiliation: Department of Respiratory, Children's Hospital of Fudan University, Shanghai 201102, China.
authors.forename: Li-Ling
authors.initials: LL
authors.lastname: Qian
authors.affiliation: Department of Respiratory, Children's Hospital of Fudan University, Shanghai 201102, China.
authors.forename: Xiao-Bo
authors.initials: XB
authors.lastname: Zhang
mesh_terms: D040981:Acinetobacter baumannii / Q000302:isolation & purification / Q000472:pathogenicity; D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D019411:Clinical Laboratory Techniques / Q000379:methods; D021902:Enterobacter aerogenes / Q000302:isolation & purification / Q000472:pathogenicity; D004926:Escherichia coli / Q000302:isolation & purification / Q000472:pathogenicity; D005260:Female; D006193:Haemophilus influenzae / Q000302:isolation & purification / Q000472:pathogenicity; D006801:Humans; D007223:Infant; D008297:Male; D009305:Nasopharynx / Q000382:microbiology*; D011446:Prospective Studies; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification / Q000472:pathogenicity; D012141:Respiratory Tract Infections / Q000175:diagnosis* / Q000382:microbiology*; D012680:Sensitivity and Specificity; D013211:Staphylococcus aureus / Q000302:isolation & purification / Q000472:pathogenicity; D013296:Streptococcus pneumoniae / Q000302:isolation & purification / Q000472:pathogenicity