Evaluation of the usefulness of routine microscopy in canine urinalysis

The initial physical signs, clinical problems, and results of 1,000 consecutive urinalyses of canine patients at the Colorado State University Veterinary Teaching Hospital were reviewed and summarized to compare microscopic and physicochemical examinations of urine. Physicochemical examination alone would have resulted in an 11.4% (64/562) false-negative rate for detection of abnormal urine specimens without consideration of patient risk for genitourinary disease. The effects of a discriminative diagnostic algorithm on macroscopic examination sensitivity were determined. Fifty-one macronegative/micropositive and 85 macro- and micronegative specimens were obtained from higher-risk patients with history, physical signs, clinical problems, or serum biochemical analysis results indicative of predisposition to genitourinary disease, which would have warranted complete urinalyses regardless of physicochemical findings. Exclusion of these patients from evaluation of physicochemical examination sensitivity in order to consider such methodology's impact as a screening procedure only for those patients whose genitourinary disease was not already suspect resulted in a significantly (P less than 0.001) lower false-negative rate of 3.05% (13/426).