title: Non-Invasive Diagnosis of Helicobacter pylori: Evaluation of Two Enzyme Immunoassays, Testing Serum IgG and IgA Response in the Anand District of Central Gujarat,India.
abstract: BACKGROUND
  Validation of an accurate and less cumbersome noninvasive method to detect current Helicobacter pylori infection is a requisite for any laboratory.
  
  
  OBJECTIVE
  The purpose of this study is to corroborate the usefulness of two commercially available kits NovaTec ELISA-A and ELISA-G, in the detection of ongoing H.pylori infection.
  
  
  METHODS
  Two hundred and twenty eight consecutive serum samples of symptomatic patients who attended the endoscopy unit of "Deep" surgical hospital, Anand, which were collected during the period from 27th February 2008 to 31st august 2011, were studied. The sera were processed and tested for the detection of the H.pylori IgG and IgA antibody by using a solid phase; capture micro well ELISA, procured from Nova Tec immunodiagnostica GmbH Germany.
  
  
  RESULTS
  IgG ELISA showed 100% sensitivity and Negative predictive value (NPV), while IgA ELISA was better in terms of specificity (61.4%) and accuracy (63%) as compared to IgG ELISA. We found 7% (16/228) of IgA positive cases with IgG negative response. IgG response was more common in reflux esophagitis patients (OR 1.451, 95%CI-0.850-2.477) and then in gastritis (OR 0.962, 95%CI-0.570-1.621) and duodenitis(OR-0.806, 95%CI-0.112-5.827), while IgA positive response was more common in duodenitis patients (OR-1.383, 95%CI-0.191-9.995) and reflux esophagitis patients (OR 1.289, 95% CI-0.756-2.197) and least in duodenal ulcer patients (OR 0.670, 95%CI-0.222-2.029).
  
  
  CONCLUSIONS
  IgG update is reliable and accurate test and can be expedient as a screening test and thus serve as an alternative to endoscopy. For the purpose of excluding infection with H.pylori, the performance of IgG is moderate (low specificity) but can be improved by conjunctional IgA testing which will offer some additional diagnostic value.
authors.affiliation: Assistant Professor, Department of Microbiology, Shree P. M. Patel College of Paramedical Science and Technology , Anand, Gujarat, India .
authors.forename: Himani Bhardwaj
authors.initials: HB
authors.lastname: Pandya
authors.affiliation: Head of the Department, Department of Biochemistry, P.D. Patel Institute of Applied Sciences, Charotar University of Science and Technology (CHARUSAT) , Changa, Gujarat, India .
authors.forename: Jagdish Shantilal
authors.initials: JS
authors.lastname: Patel
authors.affiliation: Dean, C. U, Shah Medical College , Surendranagar, Gujarat, India .
authors.forename: Harihar Hardas
authors.initials: HH
authors.lastname: Agravat
authors.affiliation: Assistant Professor (Medical Microbiology), Department of Microbiology, Shree P. M. Patel College of Paramedical Science and Technology , Anand, Gujarat, India .
authors.forename: Navneet Kumar Ramdayal
authors.initials: NK
authors.lastname: Singh
keywords: Enzyme linked immunosorbant assay (ELISA); Helicobacter pylori; Immunoglobulin A (IgA); Immunoglobulin G (IgG)