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

Abstract EN

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 46patients with non-erosive diseases (gastri¬tis or gastroduodenitis).

Sera were testedfor 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 histologi¬cal 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 examina¬tion 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 ofpositivity (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 %) fol¬lowed 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 0% 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 IgM 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.

Conclusion : The most sensitive invasive test (biopsy related) andnoninvasive (serological) tests were histologi¬cal examination and IgG immunochromatography card tests respectively.