title: In vitro increase of mean corpuscular volume difference (dMCV) as a marker for serum hypertonicity in dogs.
abstract: Spurious increase in erythrocyte mean corpuscular volume (MCV) on automated cell analyzers is a well-characterized lab error in hypertonic patients. A difference between automated and manual MCV (dMCV) greater than 2 fl has been shown to predict hypertonicity in humans. The purpose of this study was to investigate dMCV as a marker for serum hypertonicity in dogs and to examine the relationship between dMCV and three methods of estimating serum tonicity: measured (OsMM), calculated (OsMC), and calculated effective (OsMCE) osmolalities. OsMC, OsMCE, and dMCV were calculated from routine blood values and OsMM was directly measured in 121 dogs. The dMCV of hypertonic dogs was significantly larger than that of normotonic dogs for all three osmolality methods. dMCV predicted hypertonicity as estimated by OsMM better than it predicted hypertonicity as estimated by OsMC and OsMCE. A cutoff of 2.96 fl yielded the best sensitivity (76%) and specificity (71%) for hypertonicity estimated by OsMM.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA. Electronic address: jmreinha@vet.k-state.edu.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Reinhart
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA.
authors.forename: Misty R
authors.initials: MR
authors.lastname: Yancey
authors.affiliation: Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Pohlman
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Schermerhorn
mesh_terms: D000818:Animals; D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood; D004283:Dog Diseases / Q000097:blood*; D004285:Dogs; D004909:Erythrocyte Indices / Q000662:veterinary*; D005260:Female; D008297:Male; D009994:Osmolar Concentration; D012372:ROC Curve
chemical_list: D015415:Biomarkers
keywords: Endocrinology; Metabolism; Osmolality; Sodium; Tonicity