Comparison of urine dipstick, sulfosalicylic acid, urine protein-to-creatinine ratio, and species-specific ELISA methods for detection of albumin in urine samples of cats and dogs.

OBJECTIVE: To evaluate the use of dipstick, sulfosalicylic acid (SSA), and urine protein-to-creatinine ratio (UP:C) methods for use in detection of canine and feline albuminuria.

DESIGN: Evaluation study.

SAMPLE POPULATION: 599 canine and 347 feline urine samples.

PROCEDURES: Urine was analyzed by use of dipstick, SSA, and UP:C methods; results were compared with those for a species-specific ELISA to determine sensitivity, specificity, positive predictive value (PPV), negative predictive value, and positive and negative likelihood ratios.

RESULTS: Positive results for dipstick and SSA tests (trace reaction or greater) in canine urine had moderate specificity (dipstick, 81.2%; SSA, 73.3%) and poor PPV (dipstick, 34.0%; SSA, 41.8%). Values improved when stronger positive results (>or= 2+) for the dipstick and SSA tests were compared with ELISA results (specificity, 98.9% and 99.0% for the urine dipstick and SSA tests, respectively; PPV, 90.7% and 90.2% for the dipstick and SSA tests, respectively). Data obtained for cats revealed poor specificity (dipstick, 11.0%; SSA, 25.4%) and PPV (dipstick, 55.6%; SSA, 46.9%). Values improved slightly when stronger positive test results (>or= 2+) were used (specificity, 80.0% and 94.2% for the dipstick and SSA tests, respectively; PPV, 63.5% and 65.2% for the dipstick and SSA tests, respectively). The UP:C had high specificity for albuminuria in dogs and cats (99.7% and 99.2%, respectively) but low sensitivity (28.7% and 2.0%, respectively).

CONCLUSIONS AND CLINICAL RELEVANCE: Caution should be used when interpreting a positive test result of a dipstick or SSA test for canine or feline albuminuria.