title: Usefulness and limitations of rapid urine dipstick testing for joint-fluid analysis. Prospective single-center study of 98 specimens.
abstract: OBJECTIVE
  To evaluate the diagnostic performance of rapid urine reagent strip testing of joint fluid in separating mechanical from inflammatory disease.
  
  
  METHODS
  In a prospective single-center 12-month study of joint fluid specimens, leukocyte esterase reagent strip testing (LERST) was compared to leukocyte counts used as the reference standard. Leukocyte counts greater than 2000/mm(3) were taken to indicate inflammation. Reproducibility of LERST was evaluated by testing 73 specimens twice and computing Cohen's kappa coefficient.
  
  
  RESULTS
  Ninety-eight joint fluid specimens (26 with mechanical and 72 with inflammatory characteristics) were evaluated. LERST had 79.2% sensitivity, 92.3% specificity, 96.6% positive predictive value, 61.5% negative predictive value, a positive likelihood ratio of 10.3, and a negative likelihood ratio of 0.23. The kappa coefficient was 0.70 (0.53-0.87). Two negative LERSTs a few minutes apart had 80% negative predictive value and a negative likelihood ratio of 0.08.
  
  
  CONCLUSIONS
  LERST of joint fluid is a rapid means of satisfactorily separating mechanical from inflammatory joint fluids.
authors.affiliation: Service de Rhumatologie, Hôpital Sud, CHU de Rennes, 16, boulevard de Bulgarie, BP 90347, 35203 Rennes cedex 2, France. Electronic address: guillaume.coiffier@chu-rennes.fr.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Coiffier
authors.forename: Stefan
authors.initials: S
authors.lastname: Pollet
authors.forename: Jean-David
authors.initials: JD
authors.lastname: Albert
authors.forename: Aleth
authors.initials: A
authors.lastname: Perdriger
authors.forename: Pascal
authors.initials: P
authors.lastname: Guggenbuhl
authors.forename: Gérard
authors.initials: G
authors.lastname: Chales
mesh_terms: D002265:Carboxylic Ester Hydrolases / Q000032:analysis*; D006801:Humans; D007592:Joint Diseases / Q000175:diagnosis*; D007958:Leukocyte Count; D011446:Prospective Studies; D011934:Reagent Strips; D013582:Synovial Fluid / Q000737:chemistry* / Q000166:cytology; D014556:Urine / Q000737:chemistry*
chemical_list: D011934:Reagent Strips; C021443:leukocyte esterase; D002265:Carboxylic Ester Hydrolases
keywords: Diagnosis; Inflammation; Joint fluid; Reagent strip; Screening; Urine dipstick