Comparison of Serum IgA and IgG Antibodies for Detecting Helicobacter pylori Infection

Abstract

Objective Although the diagnostic utility of serum IgG antibodies to Helicobacter pylori (H. pylori) is well established, the usefulness of IgA-based tests is less well documented. The aim of this study was to evaluate two commercially available ELISAs, both for IgG and IgA.Patients and Methods Rapid urease test and histology analysis were performed in 183 patients. A patient was considered to be H. pylori-positive when either biopsy test was positive, and considered to be noninfected when both tests were negative. Intestinal metaplasia was determined by dye endoscopy with methylene blue. ELISA testing was performed using the EPI HM-CAP IgG and PP-CAP IgA assays and EIAgen IgG and IgA assays.Results

Non-Invasive Diagnosis of Helicobacter pylori: Evaluation of Two Enzyme Immunoassays, Testing Serum IgG and IgA Response in the Anand District of Central Gujarat, India

“…The IgG, evaluated in our study, had a sensitivity and negative predictive values of 100% respectively, which is almost in accordance with other studies [11][12][13] [Table /Fig-4]. The high sensitivity observed permits the safe use of the test in epidemiologic surveys.…”

“…Although we got very less specificity (108 samples were false positive), indicating that the ELISA must be validated for different populations. As it is proved earlier that sensitivity and specificity of serology depends on the gold standards used to compare the tests, the nature of the antigens employed and the value chosen for the cutoff and it is highly variable, ranging from 30%-100% [11]. Certainly other variables than this might be responsible for the differences observed between various studies, such as the severity and staging of peptic disease and the different strains of microorganism might also play a role [14].…”

Correlation of serology with morphological changes in gastric biopsy of H. pylori infection

“…15,16 In the present study, there was a slight preponderance of H. pylori infection in males (57.6%) as compared to 20 In the present study, the sensitivity, specificity, PPV and NPV of serology was 90.90%, 59.25%, 73.17% and 82.21% respectively. These results were comparable to those of Urita et al 20 She et al however, used stool antigen test as the gold standard and found lower values for specificity and PPV. 21 All the mentioned studies used ELISA technique for serology, whereas in the present study immuno chromatography technique was used.…”

Evaluation of Helicobacter pylori Immunoglobulin G (IgG), IgA, and IgM Serologic Testing Compared to Stool Antigen Testing

“…Numerous studies have evaluated these diagnostic tests but have been limited by a small sample size or restriction to either children or adults (3-9, 11-17, 19, 20). The clinical utility of serologic testing in both children and adults has been debated; moreover, it has not been established whether positive cutoff levels need to be adjusted for age (4,5,8,13,19). Immunoglobulin A (IgA) and IgG serologic tests are possibly less reliable in children than adults, but this has not been definitively established (13).…”