title: Clinical evaluation of a leukocyte esterase test-strip for detection of feline pyuria.
abstract: Commercial macroscopic test-strips (dipsticks) that indirectly detect urine leukocytes by quantifying leukocyte esterase (LE) activity have been advocated as a simple, rapid, and inexpensive alternative to microscopic examination for detection of significant pyuria in urine specimens. The purpose of this study was to evaluate the diagnostic performance of a commercial LE test-strip for detection of feline pyuria. Two hundred and thirteen consecutive urine specimens were collected from 188 different feline patients and analyzed for LE activity with a LE test-strip (Multistix 2 Reagent Strips:Ames Division, Bayer Corp., Elkhart, IN). Results of the LE test-strip were compared with those of standard urine biochemical and microscopic sediment evaluations. Compared with urine sediment leukocyte counts, the LE test-strip had a sensitivity of 77%, a specificity of 34%, positive and negative predictive values of 14 and 91 % respectively, and an overall test efficiency of 39%. Multivariable logistic regression analysis did not reveal significant associations between pyuria (>5 WBC/hpf) and a positive LE test- strip reaction; however, hematuria, lipiduria, increasing age, and decreasing urine specific gravity were associated with a significantly increased risk for positive LE test-strip reactions. We conclude that the LE test-strip evaluated in this study is highly nonspecific for detection of significant pyuria in feline urine specimens and should not replace routine microscopic urine sediment examination in this species.
authors.affiliation: Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824.
authors.forename: Kathleen M.
authors.initials: KM
authors.lastname: Holan
authors.forename: John M.
authors.initials: JM
authors.lastname: Kruger
authors.forename: SSuzanne N.
authors.initials: SN
authors.lastname: Gibbons
authors.forename: Cheryl L.
authors.initials: CL
authors.lastname: Swenson