A New Simple Immunoassay for Detecting <i>Helicobacter pylori </i>Infection: Antigen in Stool Specimens

Abstract

Background/Aim: Several diagnostic tests are available for evaluating Helicobacter pylori (Hp) infection: histological examination, culture of gastric biopsy specimens, rapid urease test, urea breath test and serology. A recently marketed direct enzyme immunoassay (HpSA) detects Hp antigen in stool samples. The aim of our study was to evaluate overall diagnostic sensitivity, specificity and positive and negative predictive values of this new diagnostic test. Methods: We included in the study 84 patients (39 males and 45 females; mean age 49.57 years) with dyspeptic symptoms who were examined by upper gastrointestinal endoscopy. Exclusion criteria were previous treatment with proton pump inhibitors, bismuth compounds or antibiotics. During the endoscopic examination biopsies were taken from antrum and corpus for Hp culture and histological examination, and stool specimens were submitted to the laboratory to be stored until the HpSA test. Hp was judged to be present when culture or histology and culture were positive. The ¹³C-urea breath test was done only in culture-negative patients in whom either histology or immunoassay or both were positive. Results: Hp was found in 55 patients by both culture and histology. Stool antigen has been detected in 54 of the 55 Hp-positive patients, giving a sensitivity of 98.2% and a negative predictive value of 96.4%. In 2 out of 29 patients HpSA gave a positive result, but the biopsy-based methods were negative, resulting in a low rate of false-positives, with 93.1% specificity and 96.4% positive predictive value; the ¹³C-urea breath test confirmed these results as negative. Conclusion: Our results show that this new test is highly sensitive and specific for the detection of Hp infection, and it is satisfactorily reproducible.

Diagnostic Accuracy of ¹³C-Urea Breath Test in the Diagnosis of <i>Helicobacter pylori</i> Infection in Patients with Partial Gastric Resection due to Peptic Ulcer Disease

“…Our results suggest that the 13 C-UBT is not a sufficient diagnostic tool to detect H. pylori infection in patients after stomach surgery. Further studies are needed to optimize the breath test or to evaluate other noninvasive tests, like the H. pylori stool test [20, 21]. Until such data are available, we recommend taking biopsy specimens especially from the fundus of the gastric remnant.…”

Clinical value ofHelicobacter pyloristool antigen test, ImmunoCard STAT HpSA, for detectingH pyloriinfection

“…Because H pylori antibody titers fall very slowly even after successful eradication, tests lack of specificity and sensitivity [5][6][7][8][9] . Recently, the H pylori stool antigen (HpSA) test has been put in the market as another noninvasive technique [10][11][12][13] , but has rarely validated in China [14] . The aim of this study is to evaluate the clinical value of a new test, ImmunoCard STAT HpSA, for the diagnosis of H pylori infection.…”

Detection of Helicobacter Pylori Antigen in Stool by Enzyme-Linked Immunosorbent Assay and Comparison With Conventional Methods

“…Thus, the HpSA test was an useful method for detecting H. pylori in patients for whom endoscopy was not indicated. Fanti et al (1999) in his study to evaluate EIA for HpSA, found that this method has a sensitivity of 98.2%, negative prediction value of 96.4%, specificity of 93.1% and a positive prediction value of 96.4%. 14 Vaira et al (1999).…”

“…Fanti et al (1999) in his study to evaluate EIA for HpSA, found that this method has a sensitivity of 98.2%, negative prediction value of 96.4%, specificity of 93.1% and a positive prediction value of 96.4%. 14 Vaira et al (1999). 15 , in a multi-centre prospective study, found a sensitivity rate of 94.1% and a specificity rate of 91.8% for HpSA testing.…”