Evaluation of haem dipstick pad, urine protein, urine pH and urine protein:creatinine ratio results as a marker of bacteriuria in dogs and cats with inactive urine sediment.

Abstract

Evaluation of haem dipstick pad, urine protein, urine pH and urine protein:creatinine ratio results as a marker of bacteriuria in dogs and cats with inactive urine sediment. Cats and dogs with contemporaneous urine dipstick, microscopic sediment analysis and microbiological culture and sensitivity results over a four-year period (2016 to 2020) were retrospectively identified. Dogs and cats with active urine sediments (at least five erythrocytes and/or five leukocytes per high-power field) and/or spermaturia were excluded. Association between urine pH, haem dipstick result, protein dipstick result and urine protein:creatinine ratio with bacteriuria were evaluated using binary logistic regression analysis. Likelihood ratios for bacteriuria were calculated at different diagnostic thresholds. A total of 668 and 169 dog and cat urine samples were included. Of these, 166 dogs (25%) had a positive urine culture, whilst only 29 cats (17%) had a positive urine culture. In dogs and cats, any positive haem dipstick result was significantly associated with bacteriuria, although only a ≥4+ haem positive result in dogs was associated with a small increase in the likelihood of a positive urine culture, and positive likelihood ratios did not support the use of haem dipstick results as a screening test for bacteriuria in cats. pH, urine protein:creatinine ratio and protein dipstick results were not associated with bacteriuria. Our findings provide proof of concept that haem dipstick pad results in dogs with inactive sediment and without spermaturia might be useful as a screening test for bacteriuria, although further studies are required to confirm these findings.