Sensitivity and specificity of laboratory based serological tests for detection of Helicobacter pylori infection compared to histopathological test

Abstract number: 1135_160

Sharifi H., Moniri R., Mehrzad V., Ehteram H., Mousavi G.A., Ahmadi H.

Objectives:  

Helicobacter pylori (HP) role in duodenal ulcer, gastric ulcer, gastritis, intestinal metaplasia, maltoma and adenocarcinoma of stomach is established. Then detection of HP by non-invasive methods such as serological test (ELISA) is important. In order to determine of sensitivity and specificity of ELISA in detection of HP infection comparing to histopathology (Gold standard) this study was done.

Methods:  

In an analytic study 232 patients with gastrointestinal signs were studied. Endocopy was done and 2–3 biopsies were taken from antrum. Specimens were processed by shandon tissue processor (citadel) and prepared sections were stained by Hematoxylin–Eosin and Giemsa. Slides were studied by two pathologist and one microbiologist. Also 5 cc blood was taken to determine anti HP (IgG) by ELISA method. Patients’ data including age, sex, clinical signs, histological diagnosis, existence of HP in biopsies and results of ELISA tests were recorded and analysed by statistical tests.

Results:  

Of 232 patients 130 (56.1%) were females and 102 (43.9%) males. They were in age group 10–80 years. The most common clinical sign of infected patients was epigastric pain and the least were hiccup and vomiting. The most common pathologic findings were chronic active gastritis with ulcer or intestinal metaplasia and then chronic active gastritis alone. In the base of histopathology 222 (95.7%) patients had HP infection, by ELISA method 197 patients were IgG positive. ELISA sensitivity was 85%. Of 10 patients who were negative in histology in 2 patients IgG was negative. Specificity of ELISA was 20%. ELISA method showed positive predictive value 95.9% and negative predictive value 5.7%.

Conclusions:  

This study showed that serologic test (ELISA method) IgG is a good test for screening but no for diagnosis. We recommend ELISA method be used for screening and then diagnostic tests such as histology or microbiology be used for definite diagnosis. There is no relation between H.P infection age, sex and clinical signs.