title: Serum protein concentrations as predictors of serum immunoglobulin G concentration in neonatal foals.
abstract: OBJECTIVE
  To determine the predictive value of serum concentrations of total protein (sTP), albumin (sAlb), and globulin (sGlob) measured by automated calorimetric assays to estimate serum immunoglobulin G (sIgG) concentrations in neonatal foals and identify failure of transfer of passive immunity when compared to turbidoimmunometric assay determinations of sIgG.
  
  
  METHODS
  Retrospective and prospective analysis of laboratory data.
  
  
  METHODS
  University tertiary care facility.
  
  
  METHODS
  Group 1 (retrospective): foals (n = 45) ≤7 days of age in which sIgG, sGlob, sAlb, and sTP concentrations were measured on an automated chemistry analyzer. Group 2 (prospective): foals (n = 31) ≤7 days of age with same laboratory data collected used to validate equations generated from group 1 foals.
  
  
  METHODS
  Spearman rank correlations between measured sIgG and serum protein concentrations were performed. When significant correlation was found, sIgG was estimated using an sGlob simple linear regression and estimated using a sGlob, sTP, and sAlb multiple linear regression. Comparisons between estimated and measured sIgG was performed using Kruskal-Wallis testing. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated to identify foals with sIgG < 8.0 g/L [<800 mg/dL].
  
  
  RESULTS
  sIgG was correlated with sGlob, sTP, and sAlb (ρ = 0.8, 0.6, and -0.3, respectively; P < 0.05). Estimated sIgG and measured sIgG were not different (P > 0.9). In group 1 foals, the sensitivity, specificity, positive predictive value, and negative predictive value were 73%, 76%, 73%, and 83%, respectively, for sGlob, and 90%, 76%, 75%, and 90%, respectively, for multiple proteins estimated sIgG identification of failure of transfer of passive immunity. Test qualities were improved in group 2 foals.
  
  
  CONCLUSIONS
  Serum protein concentrations may be used to estimate sIgG concentrations in newborn foals. Further investigation using a larger sample size is needed to validate this methodology of assessing humoral immunity in neonatal foals.
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA. Samuel.Hurcombe@cvm.osu.edu
authors.forename: Samuel D A
authors.initials: SD
authors.lastname: Hurcombe
authors.forename: Adriel L
authors.initials: AL
authors.lastname: Matthews
authors.forename: Victoria H L
authors.initials: VH
authors.lastname: Scott
authors.forename: Jarred M
authors.initials: JM
authors.lastname: Williams
authors.forename: Catherine W
authors.initials: CW
authors.lastname: Kohn
authors.forename: Ramiro E
authors.initials: RE
authors.lastname: Toribio
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000097:blood*; D001798:Blood Proteins / Q000378:metabolism*; D015331:Cohort Studies; D006736:Horses / Q000097:blood*; D007112:Immunity, Maternally-Acquired / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood*; D008954:Models, Biological
chemical_list: D001798:Blood Proteins; D007074:Immunoglobulin G