title: Comparison of stool antigen test with gastric biopsy for the detection of Helicobacter Pylori infection.
abstract: OBJECTIVE
  Helicobacter Pylori (H.pylori) is one of the most important causes of dyspepsia and diagnosis can be made by invasive or non-invasive methods. One of the non-invasive methods, H.pylori stool antigen test (HpSA) is simple, fast and relatively inexpensive. According to this view with regard to gastric biopsy as a gold standard the sensitivity, specificity, positive and negative predictive values of this method were calculated.
  
  
  METHODS
  Stool samples of 61 patients who underwent upper endoscopy and gastric biopsy due to dyspepsia were evaluated for H. Pylori stool antigen using sandwich ELISA method.
  
  
  RESULTS
  From the 61 patients who participated in this study, H.pylori was diagnosed in 38 (62.3%) gastric biopsies, 25(66%) of these had positive HpSA test. Also, of 27 (37.7%) positive HpSA cases, H.pylori was seen in 25 gastric biopsies. For this method, sensitivity of 66% with 93% positive predictive value was calculated. Also, 91% specificity with 62% negative predictive value was estimated.
  
  
  CONCLUSIONS
  High positive HpSA indicates high risk of H.pylori infection and high specificity shows that the likelihood of false positive is low. Therefore, physicians can trust on this method and start patient`s treatment.
authors.affiliation: Majid Sharbatdaran, Assistant Professor, Department of Pathology, Babol university of Medical Sciences, Babol, Iran.
authors.forename: Majid
authors.initials: M
authors.lastname: Sharbatdaran
authors.affiliation: Mehrdad Kashifard, Associate Professor, Department of Internal Medicine, Babol university of Medical Sciences, Babol, Iran.
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Kashifard
authors.affiliation: Shahriar Shefaee, Assistant Professor, Department of Pathology, Babol university of Medical Sciences, Babol, Iran.
authors.forename: Shahriar
authors.initials: S
authors.lastname: Shefaee
authors.affiliation: Sepideh Siadati, Assistant Professor, Department of Pathology, Babol university of Medical Sciences, Babol, Iran.
authors.forename: Sepideh
authors.initials: S
authors.lastname: Siadati
authors.affiliation: Babak Jahed, Pathologist, Babol university of Medical Sciences, Babol, Iran.
authors.forename: Babak
authors.initials: B
authors.lastname: Jahed
authors.affiliation: Samaneh Asgari, Master of Biostatistics, Clinical Research Development Center, Shahid Beheshti Hospital, Babol, Iran.
authors.forename: Samaneh
authors.initials: S
authors.lastname: Asgari
keywords: Dyspepsia; Gastric biopsy; Helicobacter Pylori stool antigen; Negative predictive value; Sensitivity; Specificity