Comparison of stool immunoassay with standard methods for detection of Helicobacter pylori infection in patients with upper-gastrointestinal bleeding of peptic origin

Abstract

The detection of H. pylori antigen in stools in patients with UGB of peptic origin has a good sensitivity (96.6%) but a low specificity (33.3%) for the diagnosis of H. pylori infection, which probably makes this test an inadequate tool in this setting if utilized alone.

Accuracy of Urea Breath Test Performed Immediately After Emergency Endoscopy in Peptic Ulcer Bleeding

“…The specificity found in our study for early UBT was 66.6%, which is lower than that previously reported (78-100%) [16,[20][21][22][23][24][25][26]29]. An explanation for this somewhat lower specificity could be the urease activity in oropharyngeal bacteria [17,19], which could have been swept down to the stomach at endoscopy or even due to the oxygen flow, as well as the occurrence of some borderline results very close to the selected cut-off value [30] or maybe differences in sample collection between the early and the delayed UBT; however, all samples were collected by a physician either at the moment of endoscopy or at the outpatient clinic, and changes in the cut-off value would be expected to have little effect on clinical accuracy of the test [31].…”

“…Sensitivity for early UBT was 86.3%, which is lower than previously reported in two large meta-analyses in PUB [7,16], but within the same range as published in some of the studies included in this meta-analysis [20][21][22][23][24][25][26]; sensitivity for early UBT was higher to 78% reported for UBT in patients taking PPIs [28]. Tobacco or recent presence of blood or foods in stomach could have influenced this result in our patients [16] as well as PPIs from admission to endoscopy (it is accepted that UBT has a sensitivity higher than 90% when done in patients withouth PUB).…”

“…Also, UBT accuracy determination was not the aim of most of the reviewed studies [17,[20][21][22][23][24][25][26].…”

Diagnosis, Treatment, and Outcome in Patients with Bleeding Peptic Ulcers andHelicobacter pyloriInfections

“…This statement also applies to patients with UGI bleeding [24, 26, 35, 36, 38]. The test's sensitivity is not affected by blood in the stomach and is higher than those of biopsy-based methods and other noninvasive tests [55–57].…”

“…It can be performed by enzyme-linked immunosorbent assay (ELISA) with monoclonal or polyclonal antibodies or by immunochromatographic assay with monoclonal antibodies. The sensitivity of this method is reduced by UGI bleeding when polyclonal ELISA or immunochromatographic stool antigens are used [38, 60, 61]. Furthermore, it is not reliable in patients with bleeding peptic ulcers [62].…”