title: Evaluation of mean corpuscular volume difference as a marker for serum hypertonicity during water deprivation in dogs.
abstract: OBJECTIVE
  To evaluate mean corpuscular volume difference (dMCV) as a marker for hypertonicity induced by water deprivation in dogs.
  
  
  METHODS
  5 healthy Greyhounds maintained in a research colony.
  
  
  METHODS
  Water was withheld for 24 hours. Blood and urine samples were collected before (time 0) and every 6 hours during water deprivation. Serum and urine osmolality were measured on the basis of freezing point depression, and dMCV was calculated from routine hematologic variables.
  
  
  RESULTS
  Serum and urine osmolality significantly increased and body weight decreased over time in healthy Greyhounds during water deprivation, although most dogs developed only a slight increase in serum osmolality. The dMCV also increased over time, but the value at 24 hours did not differ significantly from the value at time 0. However, a significant correlation was found between serum osmolality and dMCV. A dMCV ≥ 5 fL yielded 100% specificity for predicting hypertonicity when hypertonicity was defined as serum osmolality ≥ 310 mOsM.
  
  
  CONCLUSIONS
  dMCV may be a useful marker for detection of mild hypertonicity in dogs and may have clinical and research applications for use in screening canine populations for hypertonicity.
authors: Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506.
authors: Jennifer M
authors: JM
authors: Reinhart
authors: Misty R
authors: MR
authors: Yancey
authors: Lisa M
authors: LM
authors: Pohlman
authors: Thomas
authors: T
authors: Schermerhorn
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000097:blood / Q000503:physiopathology*; D004285:Dogs; D004909:Erythrocyte Indices / Q000662:veterinary*; D005260:Female; D008297:Male; D009994:Osmolar Concentration; D009997:Osmotic Pressure; D012680:Sensitivity and Specificity; D014868:Water Deprivation; D014883:Water-Electrolyte Imbalance / Q000097:blood / Q000503:physiopathology / Q000662:veterinary*