N Alipoor Ghorbani , A Sarafnezhad , A Mirsalehian , R Malekzadeh , Z Jadali , Gh Behzadian , M Satari ,
Volume 57, Issue 2 (8 1999)
Abstract
Helicobacter pylori (H.pylori) is the most common human infection in the world. This agent has a strong role in pathogenesis of chronic gastritis and peptic ulcers. Therefore introducing of simple and cost effective and non invasive tests are important for diagnosis of H.pylori infections. In this study 215 patient suffering from different gastrointestinal disorders referred to GI endoscopy department of Dr. Ali Shariati Hospital were selected as case and another 50 as control group, which were evaluated for H.pylori infection. Direct smear (staining with Giemsa) and urease tests were used as gold standard tests compared with IFA-IgG and culture. Sensitivity and specificity and accuracy for IFA were 94%, 86% and 90%, respectively. Absorption with campylobacter jejoni did not change the level of IgG against H.pylori. Negativity of urease test dose not show the eradication or absence of bacteria, but shows the low number of bacteria in biopsy materials. This report suggest that IFA is an advantageous, sensitive and reliable test in diagnosis of H.pylori infection.
Sarraf Nejad A, Hoodei E, Siavoshi F, Maserrat S, Jadali Z, Shahrestani T,
Volume 59, Issue 4 (9 2001)
Abstract
Helicobacter pylori (H.pylori) is the most prominent causative agent of gastroduodenal diseases all over the world. Other manifestations such as urticaria and coronary heart diseases, also are suspected to be induced by H.pylori. Non invasive methods are preferred for diagnosis and ELISA, because of its reliability, speed, sensitivity and specificity is widely preferred as diagnostic tool. Previously we have used IFA, and here, we report an indirect ELISA technique for H.pylori diagnosis. First, 9 strains, of H.pylori isolated from biopsies, were cultured, and the soluble crude antigen was used to coat ELISA plates. Antigen concentration and conjugated antiserum dilution were optimised using checker board method. In this study the gold standard was: rapid urease test, culture and direct smear. Patient serum dillution and the cut-off value was determind, using 22 negative and 30 positive confirmed samples according to ROC curve and the results were compared with a commercial kit. The sensitivity and specificity of this method were 93.2 percent and 95.4 percent respectively. A commercial ELISA Kit, was used and compared simultaneously. The sensitivity and specificity were 87.8 percent and 73 percent respectively. Therefore, regarding the acceptable sensitivity and specificity, ease of work of ELISA, being economical and non-invasive, it can be employed in diagnosis of H.pylori infection and also in epidemiological studies.
