title: Differentiating between feline pleural effusions of cardiac and non-cardiac origin using pleural fluid NT-proBNP concentrations.
abstract: OBJECTIVE
  To assess whether pleural fluid and urine amino terminal proB-type natriuretic peptide (NT-proBNP) can distinguish cardiac from non-cardiac causes of pleural effusion.
  
  
  METHODS
  Blood, urine and pleural fluid were prospectively collected from cats presenting with pleural effusion categorised as cardiac or non-cardiac in origin. NT-ProBNP concentrations were measured using a feline-specific enzyme-linked immunosorbent assay. Groups were statistically compared and receiver operating characteristic curves constructed to determine cut-offs to distinguish cardiac from non-cardiac pleural effusion in plasma, pleural fluid and urine.
  
  
  RESULTS
  Forty cats with pleural effusion (22 cardiac and 18 non-cardiac) were studied. NT-proBNP concentrations in plasma and pleural fluid were strongly correlated. Plasma (P<0·001) and pleural fluid (P<0·001) NT-proBNP concentrations and urinary NT-proBNT/creatinine ratios (P=0·035) were significantly higher in the cardiac group. After receiver operating characteristic curve analysis a plasma NT-proBNP cut-off of 214·3 pmol/mL was suggested [sensitivity=86·4% (95% CI: 66·7 to 95·3%), specificity=88·9% (95% CI: 67·2 to 96·9%)] and a pleural fluid NT-proBNP cut-off of 322·3 pmol/mL was suggested [sensitivity=100% (95% CI: 85·1 to 100%), specificity=94·4% (95% CI: 74·2 to 99·0%)]. No cut-off with adequate sensitivity and specificity for urinary NT-proBNP/creatinine ratios was suggested.
  
  
  CONCLUSIONS
  Measurement of NT-proBNP in pleural fluid distinguishes cardiac from non-cardiac causes of pleural effusion in cats.
authors.affiliation: Veterinary Clinical Sciences, The Royal Veterinary College, North Mymms, Hatfield.
authors.forename: K
authors.initials: K
authors.lastname: Humm
authors.forename: M
authors.initials: M
authors.lastname: Hezzell
authors.forename: J
authors.initials: J
authors.lastname: Sargent
authors.forename: D J
authors.initials: DJ
authors.lastname: Connolly
authors.forename: A
authors.initials: A
authors.lastname: Boswood
mesh_terms: D000818:Animals; D002371:Cat Diseases / Q000097:blood / Q000175:diagnosis* / Q000652:urine; D002415:Cats; D003404:Creatinine / Q000652:urine; D005122:Exudates and Transudates / Q000737:chemistry*; D005260:Female; D006331:Heart Diseases / Q000150:complications / Q000175:diagnosis / Q000662:veterinary*; D008297:Male; D020097:Natriuretic Peptide, Brain / Q000032:analysis* / Q000097:blood / Q000652:urine; D010446:Peptide Fragments / Q000032:analysis* / Q000097:blood / Q000652:urine; D010996:Pleural Effusion / Q000097:blood / Q000175:diagnosis / Q000209:etiology / Q000652:urine / Q000662:veterinary*
chemical_list: D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain; D003404:Creatinine