Detection of helicobacter pylori infection in dyspeptic patients by different sero-bacteriological methods

ABSTRACT

To evaluate invasive [biopsy related] tests and non-invasive [serological] tests in the diagnosis of H. pylori ninety-two adults [54 male, 38 female] presenting with dyspepsia were studied after classification into two groups on the basis of endoscopical diagnosis; 46 patients with erosive diseases [gastroduodenal ulcers or gastroduodenal erosions] and 46 patients with non-erosive diseases [gastritis or gastroduodenitis]. Sera were tested for anti -H .pylori IgG and IgM by an immunochromatography card test and ELISA respectively. Three antral biopsies were taken for biopsy urease test [BUT], bacterial culture and histological examination. Stool samples were obtained from only 30 dyspeptic cases for H. pylori antigen detection [HpSA] by an ELISA method. H. pylori was detected in 81 of 92 cases; these were positive by one or more of the gold standard tests [culture, histology and biopsy-urease test]. Histological examination yielded the highest frequency of microorganism detection [71.7%], followed by BUT [68.5%] and then bacterial culture [26.1%]. In erosive disorders the BUT gave the highest frequency of positivity [78.3%], followed by histological examination [67.4%], and then bacterial culture [41.3%] but in non-erosive disorders histological examination gave the highest positive results [76.1%] followed by BUT [58.7%] and bacterial culture [10.9%]. The overall sensitivities of BUT, histology and bacterial culture of H. pylori were 77.8%, 81.5% and 29.6% respectively. Serologically the anti -H .pylori IgG test yielded the highest frequency of positive results [80.4%], followed by HpSA test [66.7%] and the least positive was anti -H. pylori IgM test [65.2%]. In the light of the gold standard tests used [biopsy-related tests], the validity of anti -H. pylori IgG test, anti-H .pylori 1gM test and HpSA test were determined; the sensitivities being 79%, 65.4% and 75% respectively and their specificities were 9.1%, 36.4% and 66.7% respectively. The positive and negative predictive values, the positive and negative likelihood ratios of serological tests were also evaluated. The most sensitive invasive test [biopsy related] and noninvasive [serological] tests were histological examination and IgG immunochromatography card tests respectively