Pseudo-hypoproteinemia in a hyperbilirubinemic dog with immune-mediated hemolytic anemia

A 10-year-old spayed female Miniature Poodle was presented to the University of Georgia veterinary teaching hospital for evaluation of lethargy, vomiting and anorexia of 4 days' duration. Physical examination, history and a minimum database led to a diagnosis of immune-mediated hemolytic anemia accompanied by marked hyperbilirubinemia. Refractometric protein determination was within the reference interval, whereas the biuret method indicated hypoproteinemia. This discrepancy was attributed to interference of bilirubin and biliverdin with the spectrophotometric read-out of the biuret total protein assay. The albumin concentration, determined by bromcresol green, and refractometric total protein were less affected by this interference.