title: Role of rapid urease test and histopathology in the diagnosis of Helicobacter pylori infection in a developing country.
abstract: BACKGROUND
  The aim of this study was to determine the effect of commonly self-prescribed proton pump inhibitors (PPI) on the results of rapid urease test and histology for the diagnosis of H. pylori infection.
  
  
  METHODS
  One hundred-nine consecutive patients with dyspeptic symptoms attending the endoscopy suite were enrolled in this study. Antrum biopsy specimens were collected at endoscopy for the rapid urease test (Pronto Dry, Medical Instrument Corp, France) and histopathology. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and like-hood ratio of a positive and negative of Pronto Dry test were compared against histology. The gold standard test for the diagnosis of H. pylori infection was histopathology.
  
  
  RESULTS
  Sixty-one percent (66/109) patients were males with mean age of 43 +/- 14.1 years and age range 17-80 years. Fifty-two percent (57/109) were not on any medications while 48% (52/109) used PPI before presentation to the outpatients. Pronto Dry was positive in 40% (44/109) and negative in 60% (65/109). Histopathology was positive for H. pylori in 57% (62/109) and negative in 43% (47/109). The sensitivity, specificity, PPV, NPV and like-hood ratio of a positive and negative Pronto Dry test with and without PPI were 43.3%, 86.4%, 81.3%, 3.18, 0.656 and 52.8% vs 71.9%, 80%, 82.1%, 69%, 3.59 and 0.35.
  
  
  CONCLUSIONS
  This study shows that the sensitivity, specificity, NPV and PPV of rapid urease test was reduced in patients who are on PPI. The exclusive use of the rapid urease test for the diagnosis of Helicobacter pylori cannot be recommended in patients with prior PPI use.
authors.affiliation: Department of Gastroenterology and Pathology, Aga Khan University Hospital, Karachi, Pakistan. yakoobjaved@hotmail.com
authors.forename: Javed
authors.initials: J
authors.lastname: Yakoob
authors.forename: Wasim
authors.initials: W
authors.lastname: Jafri
authors.forename: Shahab
authors.initials: S
authors.lastname: Abid
authors.forename: Nadim
authors.initials: N
authors.lastname: Jafri
authors.forename: Zaigham
authors.initials: Z
authors.lastname: Abbas
authors.forename: Saeed
authors.initials: S
authors.lastname: Hamid
authors.forename: Muhammad
authors.initials: M
authors.lastname: Islam
authors.forename: Kashif
authors.initials: K
authors.lastname: Anis
authors.forename: Hasnain Ali
authors.initials: HA
authors.lastname: Shah
authors.forename: Hizbullah
authors.initials: H
authors.lastname: Shaikh
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003906:Developing Countries; D003938:Diagnostic Techniques, Digestive System; D005260:Female; D005767:Gastrointestinal Diseases / Q000382:microbiology; D016481:Helicobacter Infections / Q000150:complications / Q000175:diagnosis* / Q000201:enzymology* / Q000473:pathology; D016480:Helicobacter pylori / Q000201:enzymology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010154:Pakistan; D054328:Proton Pump Inhibitors; D013997:Time Factors; D014510:Urease / Q000378:metabolism*
chemical_list: D054328:Proton Pump Inhibitors; D014510:Urease