Development of an In-House Enzyme-Linked Immunosorbent Assay Based on Helicobacter Pylori Sonicate Whole Cell Antigen for Diagnosis of Gastroduodenal Ulcer Disease in Karachi, Pakistan

Helicobacter pylori (H. pylori) is a causative agent of gastritis, gastroduodenal ulcers and gastric adenocarcinoma. Improper diagnostic facilities are responsible for the increasing incidence of H. pylori infections in Pakistan. ELISA is a noninvasive, less expensive assay for diagnosis of H. pylori . ELISA performance is mainly based on the H. pylori strain and nature of antigen. In this study, a total of 214 gastritis and ulcer patient’s serum samples were screened for anti- H. pylori IgG antibody. A 96-well plate coated with 10 μg/ml sonicate antigen and hundred-fold diluted patient’s serum was allowed to react. After extensive washing with buffer, 1:2,000 diluted conjugated secondary antibody was added. Later substrate was added to observe positivity by measuring the intensity of color. Statistical analyses were performed, and p value of < 0.01 was taken as significant; 84 % male patients and 96 % female patients, respectively, tested positive for H. pylori , while agewise distribution was 35?45 years males (40 %) and 35?45 years females (73 %) were found highest number of H. pylori infected patients. In-house ELISA based on sonicate whole cell antigen (sELISA) showed a sensitivity of 98 %, specificity of 100 %, accuracy 98 % and κ value 0.906 with significant correlation R?0.956; p < 0.0001. We conclude that ELISA for H. pylori sero-diagnostic infection should be based on the local strain for better sensitivity and specificity. sELISA is better and reliable diagnostic assay for the diagnosis of H. pylori infection in gastric patients of Karachi, Pakistan.