title: Field testing the utility of procalcitonin and the acute infantile observation score in febrile infants 6 to 36 months old presenting to the pediatric emergency department with no obvious focus of infection.
abstract: BACKGROUND
  Serious bacterial illness (SBI) presents a diagnostic challenge in febrile infants. History, clinical signs, and laboratory information combined with experiential knowledge affects decisions to admit and treat.
  
  
  OBJECTIVE
  To assess the utility of serum procalcitonin and the Acute Infantile Observation Score (AIOS) performed at emergency department presentation in predicting (a) confirmed serious bacterial illness and (b) illness severity.
  
  
  METHODS
  Sensitivity, specificity, and likelihood ratios were calculated for C-reactive protein, white cell count, serum procalcitonin, and AIOS.
  
  
  RESULTS
  Forty-six infants were recruited. Seven had a diagnosis of SBI, 28 were moderately ill with length of stay >24 hours, and 12 were severely ill with length of stay >96 hours. The positive likelihood ratios for confirmed SBI were C-reactive protein = 5.3, procalcitonin = 0.43, white cell count = 1.9, and AIOS = 1.5.
  
  
  CONCLUSIONS
  Procalcitonin and the AIOS do not modify the diagnostic uncertainty of the ED physician assessing the febrile infant with respect to admission or antibiotic treatment above standard laboratory investigations.
authors.affiliation: Mayo General Hospital, Castlebar, Ireland. bridgetfreyne@gmail.com
authors.forename: Bridget
authors.initials: B
authors.lastname: Freyne
authors.forename: Ray
authors.initials: R
authors.lastname: Divilley
authors.forename: Ghia
authors.initials: G
authors.lastname: Kissoon-Harrison
authors.forename: Michael B
authors.initials: MB
authors.lastname: O'Neill
mesh_terms: D000208:Acute Disease; D002097:C-Reactive Protein / Q000378:metabolism; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D002675:Child, Preschool; D005260:Female; D005335:Fever of Unknown Origin / Q000097:blood*; D006801:Humans; D007223:Infant; D007239:Infections / Q000097:blood*; D018655:Lymphocyte Count; D008297:Male; D011237:Predictive Value of Tests; D011498:Protein Precursors / Q000097:blood*; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
chemical_list: C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide
keywords: AIOS; emergency department; procalcitonin; serious bacterial Iilness