title: C-reactive protein to distinguish pneumonia from acute decompensated heart failure.
abstract: BACKGROUND
  Patients with acute decompensated heart failure (ADHF) are frequently treated with unnecessary antibiotics since they are confused with pneumonia patients.
  
  
  OBJECTIVE
  To study the efficacy of measuring C-reactive protein (CRP) levels on admission and CRP velocity in differentiating ADHF from pneumonia.
  
  
  METHODS
  A retrospective observational study of ADHF and pneumonia patients admitted to a tertiary hospital during 2 years. Patients who were already treated with antibiotics on admission were excluded. Efficacy of CRP as a diagnostic marker was evaluated by using receiver operator curves (ROC).
  
  
  RESULTS
  Overall, 72 ADHF and 50 pneumonia patients were included in the study. The mean CRP levels on admission were 13.5+/-13.5 mg/L for the ADHF patients and 127+/-84 mg/L for the pneumonia patients (p<0.001). CRP increases of > or =0.56 mg/L/h were diagnostic of pneumonia. CRP levels on admission together with CRP increases had a sensitivity of 0.96 and a specificity of 0.972 (p<0.001) as markers to distinguish pneumonia from ADHF.
  
  
  CONCLUSIONS
  This study emphasizes the dynamic nature of biomarkers. Demonstrating the efficiency of repeated CRP measurements in an acute setting will provide clinicians with a valuable tool for establishing the correct diagnosis and refraining from unnecessary use of antibiotics.
authors.affiliation: Department of Internal Medicine H, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.
authors.forename: Erel
authors.initials: E
authors.lastname: Joffe
authors.forename: Dan
authors.initials: D
authors.lastname: Justo
authors.forename: Noa
authors.initials: N
authors.lastname: Mashav
authors.forename: Michael
authors.initials: M
authors.lastname: Swartzon
authors.forename: Hanan
authors.initials: H
authors.lastname: Gur
authors.forename: Shlomo
authors.initials: S
authors.lastname: Berliner
authors.forename: Yael
authors.initials: Y
authors.lastname: Paran
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002097:C-Reactive Protein / Q000378:metabolism*; D003937:Diagnosis, Differential; D005260:Female; D006333:Heart Failure / Q000097:blood / Q000175:diagnosis*; D006801:Humans; D008297:Male; D011014:Pneumonia / Q000097:blood / Q000175:diagnosis*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D002097:C-Reactive Protein