Urine protein determination in dogs and cats: comparison of dipstick and sulfasalicylic acid procedures

Protein levels in urine specimens from 91 dogs and 65 cats were evaluated by sulfasalicylic acid precipitation (SSA) and dipstick methods. The dipstick frequently yielded reactions for protein that were greater than the level of protein indicated by SSA (i.e., false positive reactions), although no false negative reactions for protein were noted. All urine specimens with protein levels equal to or greater than 100 mg/dl by SSA had dipstick results of 3 +. Results of this study suggest that dipstick analysis for urine protein is an adequate screening procedure for the selection of urines for quantitative analysis of protein and creatinine to assess proteinuria.