Utility of commercially available reagent test strips for estimation of blood urea nitrogen concentration and detection of azotemia in pet rabbits (Oryctolagus cuniculus) and ferrets (Mustela putorius furo).

Abstract

To evaluate the utility of commercially available reagent test strips for estimation of BUN concentration and detection of azotemia in pet rabbits (Oryctolagus cuniculus) and ferrets (Mustela putorius furo). 65 blood samples from 53 rabbits and 71 blood samples from 50 ferrets of various health statuses. BUN concentrations were measured with a clinical laboratory biochemical analyzer and estimated with a reagent test strip. Results obtained with both methods were assigned to a BUN category (range, 1 to 4; higher categories corresponded to higher BUN concentrations). Samples with a biochemical analyzer BUN concentration ≥ 27 mg/dL (rabbits) or ≥ 41 mg/dL (ferrets) were considered azotemic. A test strip BUN category of 3 or 4 (rabbits) or 4 (ferrets) was considered positive for azotemia. Test strip and biochemical analyzer BUN categories were concordant for 46 of 65 (71%) rabbit blood samples and 58 of 71 (82%) ferret blood samples. Sensitivity, specificity, and accuracy of the test strips for detection of azotemia were 92%, 79%, and 82%, respectively, for rabbit blood samples and 80%, 100%, and 96%, respectively, for ferret blood samples. Test strips provided reasonable estimates of BUN concentration but, for rabbits, were more appropriate for ruling out than for ruling in azotemia because of false-positive test strip results. False-negative test strip results for azotemia were more of a concern for ferrets than rabbits. Testing with a biochemical analyzer remains the gold standard for measurement of BUN concentration and detection of azotemia in rabbits and ferrets.