Comparative Evaluation of Different Diagnostic Techniques Available for Diagnosis of Helicobacter Pylori

Introduction: Multiple tests are available to determine whether a patient is infected with Helicobacter pylori. Some of the methods for identification of this organism include: direct methods like smear examination, culture, histological sections and DNA probe technique; others are indirect like urea breath test and serology. The plethora of diagnostic tests available for the presence of Helicobacter pylori indicate that none of them is 100% accurate. Material and Methods: During a period of one year of this study, blood and antral biopsy specimens from 70 dyspeptic patients and 10 control subjects were collected. All the specimens were processed within 2-3 hours. Rapid urease test, Primary smear, Culture was done on freshly prepared brian-heart infusion agar supplemented with 7% horse blood, vancomycin (6 mg/L) and amphotericin B (2 mg/L). Plates were incubated at 37°C for 7 days in mcIntosh fildes jar under microaerophilic conditions. The prescence of H.pylori was confirmed by colony morphology, secondary smear stained with Gram's stain, Oxidase test, Catalase test and Urease test. Histology was done using Heamatoxylin & Eosin staining and Giminez staining. Serology was also performed using a commercial kit - Novum Helicobacter pylori IgG and IgA ELISA manufactured in Germany. Results: Rapid urease test was positive in 51.4% with a sensitivity and specificity of 60% each. Gram's stain was positive for H.pylori in 44.2% with a sensitivity ans specificity of 62.5% and 80% respectively. Culture was positive in 4.2% cases only and had a sensitivity and specificity of 7.5% and 100% respectively. The H.pylori positivity was 68.5% by IgA serology with a sensitivity and specificity of 75% and 36.7% respectively. In the control group 30% were positive by IgG and 40% by IgA serology.