title: Validity of quantitative unspun urine microscopy, dipstick test leucocyte esterase and nitrite tests in rapidly diagnosing urinary tract infections.
abstract: OBJECTIVE
  Rapid diagnostic tests can screen out negative samples and can save valuable time and money. The study was conducted to assess the usefulness of leukocyte esterase, nitrate reductase and quantitative microscopic unspun urine wet mount examination in rapidly diagnosing urinary tract infections (UTI).
  
  
  METHODS
  Four hundred and fifty samples were tested by semi-quantitative culture on cysteine lactose electrolyte deficient medium, microscopic examination of unspun urine for significant pyuria, dipstick leucocyte esterase test (LET) and nitrite test (NT). Culture was used as gold standard to evaluate the performance of direct microscopy and dipstick tests.
  
  
  RESULTS
  Urine culture examination revealed significant bacteriuria (>10(5) cfu/ml) 98 (21.8%), in urine samples. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and the diagnostic odds ratio (DOR) of the dip-stick LET were 73.5%, 58.5%, 33.0%, 88.8%, and 3.9 respectively; those of the dip-stick NT were 57.1%, 78.7%, 42.7%, 86.8%, and 4.9 respectively; and those for microscopic significant pyuria detection were 68.4%, 60.8%, 32.7%, 87.3%, and 3.4 respectively. Highest sensitivity (95.9%), NPV (97.9%) and DOR (25.7) was obtained on combining microscopy and dip-stick LET and NT (either of them positive). This can potentially cut costs by 79%.
  
  
  CONCLUSIONS
  Quantitative unspun urine wet mount microscopy and dipstick tests for leucocyte esterase and nitrite test should be added into routine laboratory practices for faster diagnosis of UTI.
authors.affiliation: Department of Medical Microbiology, PGIMER, Chandigarh.
authors.forename: N
authors.initials: N
authors.lastname: Taneja
authors.forename: S S
authors.initials: SS
authors.lastname: Chatterjee
authors.forename: M
authors.initials: M
authors.lastname: Singh
authors.forename: S
authors.initials: S
authors.lastname: Sivapriya
authors.forename: M
authors.initials: M
authors.lastname: Sharma
authors.forename: S K
authors.initials: SK
authors.lastname: Sharma
mesh_terms: D002265:Carboxylic Ester Hydrolases / Q000652:urine*; D005069:Evaluation Studies as Topic; D006801:Humans; D008853:Microscopy / Q000379:methods; D009573:Nitrites / Q000652:urine*; D011237:Predictive Value of Tests; D011776:Pyuria / Q000175:diagnosis / Q000652:urine*; D011934:Reagent Strips; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014552:Urinary Tract Infections / Q000175:diagnosis* / Q000382:microbiology; D014556:Urine / Q000382:microbiology*
chemical_list: D009573:Nitrites; D011934:Reagent Strips; C021443:leukocyte esterase; D002265:Carboxylic Ester Hydrolases