Evaluation of two commercially available rapid stool antigen tests for the diagnosis of Helicobacter pylori infection

INTRODUCTION

Helicobacter pylori (H. pylori) is one of the most prevalent infections, which can cause chronic gastritis, peptic ulcers and even gastric cancer. Prompt diagnosis and subsequent eradication are essential. Many commercially available H. pylori stool antigen diagnostic kits are used. However, the diagnostic performance of these tests has not yet been evaluated. This study aimed to evaluate two commercial rapid H. pylori Stool Antigen-Lateral Flow Immunochromatography Assay kits (HpSA-LFIA).

METHODOLOGY

A total of 88 adult patients with dyspeptic symptoms were included in the study. Full case history was obtained, and fresh stool samples were tested for HpSA by two different kits: RightSign® (BiotesT, Hangzhou, China) and OnSite® (CTK biotech, Poway, USA) and HpSA-enzyme-linked immunosorbent assay (ELISA) as a reference standard.

RESULTS

Of the 88 patients, H. pylori infection was positive in 32 (36.4%), negative in 53 (60.2%), and indeterminate in 3 (3.4%) by ELISA. The sensitivity, specificity, positive predictive value, and negative predictive value were as follows: 96.6%, 66.1%, 62%, and 97.4%, respectively for RightSign® test and 96.9%, 50%, 52.5%, and 96.6%, respectively for OnSite® test.

CONCLUSIONS

HpSA-LFIA, RightSign® and OnSite®, are good negative tests, however they cannot be used as a sole test for diagnosis and needs other confirmatory tests in case of positive results.

Performances of the IDEIA HpStAR Stool Antigen Test in Detection of Helicobacter pylori Infection Before and After Eradication Treatment in Algerian Children

We aimed to evaluate in an Algerian pediatric population the diagnostic performances of the IDEIA HpStAR noninvasive stool antigen test (Oxoid, Cambridge, UK) to detect Helicobacter pylori infection before and after eradication therapy. A prospective study including 158 symptomatic Algerian children was conducted. Patients were initially diagnosed with invasive (culture, histology, and rapid urease test) and noninvasive tests (urea breath test and IDEIA HpStAR test). Infected patients were treated, and 101 were controlled after treatment with two invasive (culture and histology) and two noninvasive tests (urea breath test and IDEIA HpStAR test). In Algerian children, the IDEIA HpStAR test showed good performances for initial detection of H. pylori infection and also for subsequent control of eradication treatment. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of IDEIA HpStAR test before treatment were 93.6%, 100%, 100%, 87.3%, and 96%, respectively, and those after treatment were 100, 92.8, 78.6, 100, and 94.2%, respectively.

Evaluation of a Novel Stool Antigen Rapid Test Kit for Detection of Helicobacter pylori Infection

The Quick Chaser H. pylori (QCP), which is a novel antigen detection kit for Helicobacter pylori, was developed recently. The previous examination kits targeted the catalase of H. pylori; however, this new test kit, to the best of our knowledge, is the first kit to target the flagellar protein of H. pylori The present study aimed to evaluate the efficacy of QCP compared with that of the already commercially available rapid test kit Testmate Rapid Pylori Antigen (TRP). TRP and QCP were utilized in 71 participants. The positive and negative concordance ratios of QCP to TRP were 100% (57/57) and 92.9% (13/14), respectively. Sensitivity based on the rapid urease test and culture test was 92.3%. Results of the dilution sensitivity test showed that QCP was eight times more sensitive to an H. pylori standard strain and the clarithromycin (CAM)-resistant clinical isolate and four times more sensitive to a CAM-susceptible clinical isolate than TRP. For the cross-reactivity test, 27 strains that exist in human feces, such as the Helicobacter genus, Bifidobacterium genus, Lactobacillus genus, and other resident bacteria, were selected. The results obtained using QCP were all negative, and no cross-reaction was observed. In conclusion, compared with TRP, QCP can detect H. pylori using clinical specimens with high sensitivity, regardless of CAM susceptibility and tolerance. No cross-reactivity was observed with other intestinal bacteria in humans. The kit is considered extremely useful in clinical settings.

The utility of the Helicobacter pylori stool antigen test in managing dyspepsia: an experience from a low resource setting

BACKGROUND

Dyspepsia is defined as a chronic or recurrent pain or discomfort centered in the upper abdomen. Endoscopy is the best strategy for confirming the cause of dyspepsia. Non- invasive strategies would be more appropriate in low resource countries where endoscopy is not readily available. However, there is concern that these strategies may miss serious disease like gastric cancer. One test that needs to be assessed in this regard is the Helicobacter pylori stool antigen test (HPSAT).

OBJECTIVE

To determine the validity of the stool antigen test in predicting H. pylori associated disease among patients with dyspepsia.

METHODS

In this prospective study patients with dyspepsia attending Mulago Hospital were recruited consecutively. Helicobacter pylori was determined using the Rapid Strip HpSA ®, endoscopy and gastric mucosal biopsy were done.

RESULTS

167 patients with dyspepsia were recruited into the study. There were ninety six (57.5%) females and seventy one (42.5%) males with an average age of 48.1(±18.1) years. Patients presenting with dyspepsia in Mulago hospital were more likely to come from the Central 60 (36%) and western tribes 55 (33%). The commonest endoscopic finding was oesophagitis 25 (15%). Peptic ulcer disease was found in 32 (19.2%) and 54 (32.3%) had normal endoscopy findings. H pylori was found in 33.5% and 32.5% using the HPSAT and histology respectively. The validity of the HPSAT in predicting H.pylori associated diseases was generally low with an overall sensitivity of 55.8%, and specificity of 74.2%. However, the validity was higher in predicting the diagnosis of peptic ulcer disease with a sensitivity 59.4% and specificity 72.6%.

CONCLUSION AND RECOMMENDATIONS

The HPSAT may be used in the test and treat strategy for young patients with dyspepsia without alarm signs and symptoms in low resource settings. However, because of its low validity in predicting H.pylori associated disease, it is important to follow up patients so that if symptoms persist or recur endoscopy is performed.