title: Comparison of whole blood and plasma colloid osmotic pressure in healthy cats.
abstract: OBJECTIVE
  To establish reference intervals for whole blood and plasma colloid osmotic pressure (COP) in healthy cats between the ages of 1 and 10 years using a cage-side colloid osmometer.
  
  
  METHODS
  Prospective, observational study.
  
  
  METHODS
  University veterinary teaching hospital.
  
  
  METHODS
  Sixty-three healthy cats.
  
  
  METHODS
  Phlebotomy.
  
  
  RESULTS
  Whole blood COP mean was 24.4 (±2.78) mmHg and plasma COP mean was 24.3 (±2.59) mmHg. Reference interval for our study population of feline whole blood COP was 18.9 to 30.4 mmHg, and for our study population of feline plasma COP was 18.3 to 30.8 mmHg. Difference of paired whole blood COP and plasma COP was +0.23 ± 1.68 mmHg (P = 0.32). There was no significant difference when comparing COP from neutered male and neutered female cats. Total protein and albumin were significantly correlated with whole blood COP (total protein to whole blood COP P < 0.0001, r = 0.53; albumin to whole blood COP P <0.0001, r = 0.68) and plasma COP (total protein to plasma COP P = 0.0025, r = 0.41; albumin to plasma COP P < 0.0001, r = 0.66).
  
  
  CONCLUSIONS
  No significant difference was found between mean whole blood and plasma COP in this study population of cats. Even though not statistically significant, evaluation of paired whole blood COP and plasma COP did reveal a slight difference; therefore, it seems prudent to maintain sample consistency for serial evaluations in cats.
authors.affiliation: Department of Veterinary Medicine and Surgery, University of Missouri College of Veterinary Medicine, 900 East Campus Drive, Columbia, MO, 65211.
authors.forename: Mary L
authors.initials: ML
authors.lastname: Jackson
authors.forename: Marie E
authors.initials: ME
authors.lastname: Kerl
authors.forename: Beth
authors.initials: B
authors.lastname: Tynan
authors.forename: F A
authors.initials: FA
authors.lastname: Mann
mesh_terms: D000818:Animals; D001790:Blood Physiological Phenomena; D001798:Blood Proteins / Q000032:analysis; D002415:Cats / Q000097:blood*; D003102:Colloids / Q000032:analysis; D005260:Female; D008297:Male; D009997:Osmotic Pressure; D010949:Plasma; D011446:Prospective Studies; D012016:Reference Values
chemical_list: D001798:Blood Proteins; D003102:Colloids
keywords: albumin; colloid; oncotic pressure; osmometry; total protein