Laboratory diagnosis of canine uroperitoneum based on cellular and biochemical characteristics of serum and abdominal fluid

Abstract

Background Literature on the laboratory diagnosis of uroperitoneum is scarce, and it is mostly based on the biochemical findings of cavitary fluid and serum. Cell count and protein concentrations measurements are rarely used and available studies on this subject are based on a relatively small cohort of individuals. Objectives We aimed to use a large sample pool of dogs to establish cutoff points for biochemical analytes in cavitary fluids and serum for the diagnosis of uroperitoneum. We also sought to evaluate the general classification of these cavitary fluids. Methods In a retrospective and prospective study, 180 canine abdominal effusion cases were evaluated, 30 of which were uroperitoneum (uroperitoneum group, UG) and 150 with other etiologies (non‐uroperitoneum group, NUG). Results The results showed that 83.3% of UG and 12.7% of NUG abdominal fluid cases were not classified as transudates or exudates. The use of specific cutoffs for fluid creatinine concentrations (≥2.1 mg/dL) and fluid:serum creatinine ratios (Cf: Cs ≥ 1.25) in these unclassified effusions resulted in an accuracy of 99.0% for the laboratory diagnosis of uroperitoneum. Conclusions The adoption of a new set of criteria and cutoffs based on the combination of parameters such as TP, TNCC, fluid creatinine and Cf: Cs improves the diagnosis of uroperitoneum in dogs.