title: Can serum procalcitonin levels help interpret indeterminate chest radiographs in patients hospitalized with acute respiratory illness?
abstract: BACKGROUND
  Clinical diagnosis of pneumonia is difficult and chest radiographs often indeterminate, leading to incorrect diagnoses and antibiotic overuse.
  
  
  OBJECTIVE
  To determine if serum procalcitonin (ProCT) could assist in managing patients with respiratory illness and indeterminate radiographs.
  
  
  METHODS
  Subjects were prospectively enrolled during 2 consecutive winters.
  
  
  METHODS
  A 520-bed hospital in Rochester, NY.
  
  
  METHODS
  Five hundred twenty-eight adults admitted with acute respiratory illness were enrolled.
  
  
  METHODS
  Serum ProCT, admission diagnoses, and chest radiographic findings were used to derive receiver operating characteristics curves to assess predictive accuracy of ProCT for the presence of infiltrates.
  
  
  RESULTS
  Subjects with pneumonia had higher ProCT (median 0.27 ng/ml) than those with exacerbations of chronic obstructive pulmonary disease (0.08 ng/ml), acute bronchitis (0.09 ng/ml), or asthma (0.06 ng/ml). ProCT had moderate accuracy for the presence of infiltrates (area under curve [AUC] 0.72), when indeterminate radiographs were independently classified as infiltrates by a pulmonologist evaluating patients.
  
  
  CONCLUSIONS
  ProCT may be useful in diagnosing pneumonia when chest radiographs are indeterminate.
authors.affiliation: Department of Medicine, University of Rochester, Rochester, NY, USA. edward.walsh@rochestergeneral.org
authors.forename: Edward E
authors.initials: EE
authors.lastname: Walsh
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Swinburne
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: Becker
authors.forename: Eric S
authors.initials: ES
authors.lastname: Nylen
authors.forename: Richard H
authors.initials: RH
authors.lastname: Snider
authors.forename: Andrea
authors.initials: A
authors.lastname: Baran
authors.forename: Derick R
authors.initials: DR
authors.lastname: Peterson
authors.forename: Ann R
authors.initials: AR
authors.lastname: Falsey
mesh_terms: D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D005260:Female; D006760:Hospitalization / Q000639:trends; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011498:Protein Precursors / Q000097:blood*; D013902:Radiography, Thoracic; D012141:Respiratory Tract Infections / Q000097:blood* / Q000000981:diagnostic imaging*
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D015740:Calcitonin Gene-Related Peptide