Diagnosis of Helicobacter pylori infection in dyspeptic patients by stool antigen detection usefulness of a new monoclonal enzyme immunoassay test

Development of an immunochromatographic lateral flow device for rapid detection of Helicobacter pylori stool antigen

OBJECTIVE

Helicobacter pylori stool antigen (HpSA) test is a convenient and reliable non-invasive diagnosis for H. pylori infection. The aim of this study is to develop an immunochromatographic testing device for rapid detection of HpSA among Chinese patients.

DESIGN AND METHODS

Monoclonal antibodies (McAb) targeting H. pylori were developed by conventional methods and paired by sandwich ELISA. The lateral flow device (LFD) was prepared using the selected McAb pair. A total of 867 clinically separated bacterial strains, including 56H. pylori strains, were employed to test the sensitivity and specificity. Subsequently, the LFD was used to test 1200 human fecal samples, with a commercial HpSA testing device as comparison.

RESULTS

Two McAb pairs targeting H. pylori, DF2a/EE10b and IH10b/EE10b, were developed and proven to be of high specificity and sensitivity. After testing the cultures of 56 clinically separated H. pylori strains, the final LFD product was prepared using the mixture of DF2a and IH10b as capture antibodies and EE10b as the detection antibody. The testing threshold for H. pylori culture was 1.0 × 10(4)cfu/mL. The sensitivity and specificity were both 100% for the 867 tested bacterial cultures. The testing results of 1200 fecal samples showed that the positive and negative agreement rates between the homemade LFD and the commercial testing device were 99.75% and 99.87%, respectively.

CONCLUSION

Our homemade HpSA LFD can be a very promising testing device for rapid diagnosis and epidemic screening of H. pylori infection among Chinese patients.

Diagnostic performance of urea breath test, rapid urea test, and histology for Helicobacter pylori infection in patients with partial gastrectomy: a meta-analysis

BACKGROUND

Helicobacter pylori infection has been implicated in the pathogenesis of gastroduodenal diseases such as recurrent peptic ulceration and particularly residual stomach cancer in the postoperative stomach.

AIM

To determine the performance of different commonly used tests for the diagnosis of H. pylori infection in patients after partial gastrectomy.

METHODS

A systematic literature search was conducted by searching the PubMed, EMBASE and ScienceDirect databases with relevant key words. Data extraction was independently performed by two reviewers. Meta-analyses were performed for the performance of the different tests including the sensitivities, specificities, likelihood ratios (LRs), diagnostic odds ratio diagnostic odds ratio, and the summary receiver operating characteristic summary receiver operating characteristic curve. The meta-analysis was performed by Meta-DiSc software.

RESULTS

Studies showed a high degree of heterogeneity. Pooled sensitivity, specificity, LR+, LR- and diagnostic odds ratio for the different methods were: Urea breath test (9 studies): 0.77 (95% CI, 0.72-0.82), 0.89 (95% CI, 0.85-0.93), 6.32 (95% CI, 3.22-12.42), 0.27 (95% CI, 0.17-0.43), and 27.86 (95% CI, 13.27-58.49). Rapid urease test (7 studies): 0.79 (95% CI, 0.72-0.84), 0.94 (95% CI, 0.90-0.97), 10.21 (95% CI, 5.94-17.54), 0.28 (95% CI, 0.22-0.36) and 49.02 (95% CI, 24.24-99.14). Histology (3 studies): 0.93 (95% CI, 0.88-0.97), 0.85 (95% CI, 0.73-0.93), 5.88 (95% CI, 3.26-10.60), 0.09 (95% CI, 0.05- 0.15), and 97.28 (95% CI, 34.30-275.95). The corresponding summary receiver operating characteristic curves showed areas under the curves of 0.91, 0.93 and 0.96 and Q* values of 0.84, 0.86 and 0.91, respectively

CONCLUSION

Among the three commonly used tests, histological examination performs the best, followed by the rapid urease test, for the diagnosis of H. pylori infection after partial gastrectomy. Thus, histology, preferably after the rapid urease test, is recommended for the diagnosis of H. pylori infection after partial gastrectomy.

Diagnostic value of rapid urease test and urea breath test for Helicobacter pylori detection in patients with Billroth II gastrectomy: a prospective controlled trial

AIM

The aim of this work was to assess the reliability of rapid urease test (RUT) and urea breath test (UBT) for detecting Helicobacter pylori (H. pylori) in patients with Billroth II (BII) gastrectomy, using histology as reference.

METHODS

In this prospective controlled study, 31 consecutive patients with BII gastrectomy and 73 controls who had an indication for endoscopy were included. Their H. pylori status was assessed with biopsies for histology, RUT and UBT. Histology served as the gold standard. Only the biopsies from the gastric fundus were evaluated. Specificity, sensitivity, positive and negative predictive value, degree of agreement and k-statistics were used.

RESULTS

RUT and UBT for detecting H. pylori in the control group had excellent agreement [97%, kappa (k)=0.94 and 99%, k=0.97 respectively] with biopsies. In BII patients, RUT from fundic biopsies had very good agreement (87%, k=0.74) compared to histology from fundic biopsies, whereas the UBT was unreliable (agreement: 71%, k=0.41) compared to histology.

CONCLUSION

The RUT from fundic biopsies in BII patients is a reliable test for H. pylori detection, whereas the UBT is unreliable.

"Cervia II Working Group Report 2006": guidelines on diagnosis and treatment of Helicobacter pylori infection in Italy

Proper management of Helicobacter pylori infection in clinical practice--when supported by evidence-based data--is expected to produce substantial cost-efficacy advantages. This consideration has prompted the Cervia Working Group to organise a meeting of experts to update the National Guidelines on the diagnosis and treatment of H. pylori infection in Italy. Recommendations in the new European Guidelines were considered in the National setting, here in the light of factors such as the incidence of gastric cancer and gastric lymphoma, the accessibility to different diagnostic tools, the prevalence of bacterial resistance against antibiotics, and the availability of different drugs. The main revisions in respect to the previous guidelines include H. pylori eradication in non-ulcer dyspepsia patients and in non-steroidal, anti-inflammatory drug users, as well as in patients with idiopathic thrombocytopenic purpura and iron deficiency anaemia. The stool antigen test is now accepted as a valid test for confirmation of H. pylori eradication following therapy. New therapeutic approaches have been recommended for both first- (sequential therapy) and second-line (levofloxacin-based) treatment in our country.

Helicobacter pylori detection and antimicrobial susceptibility testing

The discovery of Helicobacter pylori in 1982 was the starting point of a revolution concerning the concepts and management of gastroduodenal diseases. It is now well accepted that the most common stomach disease, peptic ulcer disease, is an infectious disease, and all consensus conferences agree that the causative agent, H. pylori, must be treated with antibiotics. Furthermore, the concept emerged that this bacterium could be the trigger of various malignant diseases of the stomach, and it is now a model for chronic bacterial infections causing cancer. Most of the many different techniques involved in diagnosis of H. pylori infection are performed in clinical microbiology laboratories. The aim of this article is to review the current status of these methods and their application, highlighting the important progress which has been made in the past decade. Both invasive and noninvasive techniques will be reviewed.

Helicobacter pylori and Clostridium difficile in cystic fibrosis patients

We describe the prevalence of H. pylori and toxigenic Clostridium difficile (CD) infection and its relationship with gastrointestinal symptoms and pancreatic sufficiency (PS) or insufficiency (PI) in cystic fibrosis (CF) patients. Stool specimens from 30 consecutive patients with CF, aged 1-44, and from 30 healthy similarly aged subjects were tested for the H. pylori antigen by specific monoclonal antibodies and for CD toxins by Tox A/B assay and Tox A assay. CF patients were assessed clinically and tested for specific H. pylori serum antibodies and for mutations. In CF patients, the prevalence of H. pylori antigen was 16.6% (5/30), compared to 30% (9/30) in controls. Of the 26 CF patients with PI, only 2 (7.6%) were infected by H. pylori, compared with 3 of the 4 (75%) patients with PS (P=0.001). H. pylori infection was diagnosed in 3 of 5 (60%) CF patients carrying mild mutations, compared to 1 of 25 (4%) CF patients carrying severe mutations (P=0.01). Fourteen of 30 (46.6%) stool specimens from CF patients tested positive in the ToxA/B assay, and 3 of 14 tested positive for ToxA. No significant differences in antibiotic use, severity of lung disease, PI, chronic abdominal pain, or genotype were found between the two groups. None of the controls was positive for CD toxins. Prevalence of H. pylori infection in CF patients was lower than in similarly aged non-CF controls. CF patients with PI or a history of distal intestinal obstruction syndrome and those carrying mutations associated with a severe phenotype were protected against H. pylori infection. Almost half of the CF patients were asymptomatic carriers of CD producing mostly toxin B. More studies are needed to confirm our results in a larger group of CF patients.

Evaluation of four different fecal tests for determination of cure after Helicobacter pylori treatment

BACKGROUND

Data evaluating the monoclonal tests for determination of cure after Helicobacter pylori treatment are scarce.

GOALS

This study was aimed to evaluate the usefulness of 4 stool tests-2 new RAPID monoclonal immunochromatographic tests (RAPID Hp StAR, DakoCytomation, Cambridge, UK and ImmunoCard STAT! HpSA, Meridian Diagnostics, Cincinnati, OH) a monoclonal EIA test (Amplified IDEIA Hp StAR, DakoCytomation, Cambridge, UK), and a polyclonal EIA test (Premier Platinum HpSA, Meridian Diagnostics, Cincinnati, OH)-to confirm cure of H. pylori infection after eradication treatment.

STUDY

Ninety-seven patients who underwent eradication treatment were included. Cure of H. pylori infection was determined using 2 consecutive reference tests. Fecal tests were performed according to the specifications of the manufacturer. Sensitivity, specificity, and positive and negative predictive values were calculated.

RESULTS

After H. pylori eradication, the RAPID Hp StAR test has a sensitivity of 73% for detecting persistent infection, a specificity of 96% to 98%, a positive predictive value of 73% to 80% and a negative predictive value of 96%. For ImmunoCard STAT! HpSA the corresponding values were 91%, 97%, 77%, and 99%, for Amplified IDEIA Hp StAR 73%, 97%, 73%, and 97%, and for Premier Platinum HpSA 91%, 79%, 35%, and 98%.

CONCLUSIONS

All tests except Premier Platinum HpSA were highly accurate confirming eradication after treatment.

Accuracy of monoclonal stool antigen test for the diagnosis of H. pylori infection: a systematic review and meta-analysis

OBJECTIVE

To perform a systematic review and a meta-analysis of accuracy of monoclonal stool antigen test (SAT) for the diagnosis of Helicobacter pylori infection.

SELECTION OF STUDIES

assessing the accuracy of monoclonal SAT for the diagnosis of H. pylori infection.

SEARCH STRATEGY

electronic and manual bibliographical searches.

DATA EXTRACTION

independently done by two reviewers.

DATA SYNTHESIS

meta-analyses combining the sensitivities, specificities, and likelihood ratios (LRs) of the individual studies.

RESULTS

Twenty-two studies, including 2,499 patients, evaluated the monoclonal SAT before eradication therapy. Pooled sensitivity, specificity, LR+, and LR- were: 0.94 (95% CI 0.93-0.95), 0.97 (0.96-0.98), 24 (15-41), and 0.07 (0.04-0.12). The accuracy of both monoclonal and polyclonal SAT was evaluated together in 13 pretreatment studies, and higher pooled sensitivity was demonstrated with the monoclonal technique (0.95 vs 0.83). Twelve studies, including 957 patients, assessed the monoclonal SAT to confirm eradication after therapy. Pooled sensitivity, specificity, LR+, and LR- were 0.93 (0.89-0.96), 0.96 (0.94-0.97), 17 (12-23), and 0.1 (0.07-0.15). Both tests were evaluated together in eight post-treatment studies and, again, the monoclonal technique showed higher sensitivity (0.91 vs 0.76). Heterogeneity among studies disappeared when a single outlier study was excluded. Subanalysis depending on the reference method, the study population, or the study quality showed similar results.

CONCLUSION

Monoclonal SAT is an accurate noninvasive method both for the initial diagnosis of H. pylori infection and for the confirmation of its eradication after treatment. The monoclonal technique has higher sensitivity than the polyclonal one, especially in the post-treatment setting.

Comparison of a monoclonal with a polyclonal antibody-based enzyme immunoassay stool test in diagnosing Helicobacter pylori infection before and after eradication therapy

BACKGROUND

Detection of Helicobacter pylori antigen in stool samples has been a subject of controversy. However, it has been included in several clinical guidelines as a recommended non-invasive testing procedure in dyspeptic patients.

AIM

To compare a monoclonal enzyme immunoassay for detection of H. pylori stool antigen (Amplified IDEIA HpStAR, DakoCytomation) with a polyclonal enzyme immunoassay (HpSA test, Premier Platinum HpSA, Meridian Diagnostics) in diagnosing infection and in determining H. pylori status after eradication treatment.

METHODS

We evaluated stool samples of 198 patients diagnosed with H. pylori infection and of 41 patients without infection. The results of the monoclonal enzyme immunoassay HpStAR were compared with those of the polyclonal enzyme immunoassay HpSA.

RESULTS

The sensitivity and specificity of HpStAR were 91.9% and 70.7%, while those of HpSA were 89.4% and 80.5%, respectively. In the 126 patients evaluated 6 weeks after eradication therapy, the overall agreement between urea breath test and HpStAR was 90.5% (P = 0.710) and between urea breath test and HpSA was 76.9% (P = 0.410).

CONCLUSIONS

HpStAR is a rapid and easy-to-perform test with similar sensitivity to HpSA in the diagnosis of H. pylori infection, although it had lower specificity. In contrast, HpStAR is more accurate after eradication therapy than HpSA.

Accuracy of a new monoclonal stool antigen test in post-eradication assessment of Helicobacter pylori infection: comparison with the polyclonal stool antigen test and urea breath test

BACKGROUND AND AIM

The enzyme immunoassay based on polyclonal antibodies (HpSA) represents a valid method for the detection of Helicobacter pylori antigens in stool specimens, but some controversial results were reported in post-eradication setting. A new monoclonal enzyme immunoassay (FemtoLab H. pylori, Connex) has been developed. The present study compares the diagnostic accuracy of the two tests after eradication therapy.

PATIENTS AND METHODS

Stool samples were collected and urea breath test and endoscopy performed in 325 patients (161 F, 164 M, age 17-78 years), 4-8 weeks after standard triple eradication therapy. The FemtoLab and HpSA tests were performed in accordance with the manufacturer's protocol. H. pylori infection was confirmed if culture alone or both urease test and histology were positive and was considered absent if all three tests were negative.

RESULTS

H. pylori was eradicated in 231 patients (71.1%). Urea breath test showed the best performances with sensitivity 98.9% and specificity 99.5%. The sensitivity of FemtoLab was 88.3%, specificity 94.8%, positive and negative predictive values 87.4% and 95.2%. Corresponding HpSA values were 73.4%, 97.8%, 93.2% and 90%. Sensitivity and negative predictive value of FemtoLab were significantly better than HpSA. Adjusting the cut-offs according to a ROC curve improved not significantly the sensitivity of the two tests.

CONCLUSIONS

Urea breath test shows the best accuracy in the assessment of H. pylori infection. Between the stool tests, the FemtoLab due to its higher sensitivity is to prefer in the post-eradication assessment of H. pylori infection.

Diagnosis of Helicobacter pylori Infection

A large number of studies on diagnostic tests have been published this year. New tests were proposed for the detection of Helicobacter pylori antigens in stools and new molecular methods (real-time polymerase chain reaction) to look for antimicrobial susceptibility. The other standard tests have been applied in different situations to improve the diagnosis of the infection.

Usefulness of non-invasive tests for diagnosing Helicobacter pylori infection in patients undergoing dialysis for chronic renal failure

BACKGROUND

Helicobacter pylori infection in chronic renal failure patients has been linked to peptic ulcer and gastric neoplasia after kidney transplantation. It may also contribute to the accelerated arteriosclerosis that is usual in this population. Few data are available on the usefulness of noninvasive diagnostic tests for H. pylori infection in dialyzed patients, especially regarding the new fecal antigen detection tests. The objective of this study was to determine the efficacy of a noninvasive test for H. pylori infection in patients with chronic renal failure.

METHODS

Eighty-six patients were included in a cross-sectional study. Urea breath test, serology and three fecal tests--FemtoLab H. pylori (Connex, Germany), Premier Platinum HpSA (Meridian, USA) and Simple H. pylori (Operon SA, Spain) were performed. Helicobacter pylori status was determined by concordance of the tests. Sensitivity, specificity and positive and negative predictive values were calculated for each test.

RESULTS

Sensitivity, specificity, positive and negative predictive values were 94%, 96%, 94% and 96% for the urea breath test; 97%, 64%, 66% and 97% for serology; 86%, 100%, 100% and 91%, for FemtoLab H. pylori; 58%, 96%, 91% and 76% for Premier Platinum HpSA and 61%, 78%, 74% and 67% for Simple H. pylori.

CONCLUSIONS

The urea breath test seems to be the most reliable diagnostic method for H. pylori infection in patients with chronic renal failure. Serology has a low specificity, and the results of the fecal tests vary widely.

Comparison of two different stool antigen tests for the primary diagnosis of Helicobacter pylori infection in turkish patients with dyspepsia

AIM

To assess the reliability of two different enzyme immunoassays in detecting the Helicobacter pylori status in stool specimens of Turkish patients with dyspepsia.

MATERIALS AND METHODS

One hundred and fifty-one patients [74 with nonulcer dyspepsia (NUD), 64 with duodenal ulcer (DU) and 13 with gastric cancer] who were admitted to the endoscopy unit of Istanbul University, Cerrahpasa Medical Faculty for upper gastrointestinal endoscopy because of dyspepsia were enrolled in the study. Helicobacter pylori infection was confirmed in all patients by histology, rapid urease test and culture. A patient was classified as being H. pylori-positive if the culture alone or both the histology and the rapid urease test were positive and as negative only if all of these tests remained negative. Stool samples were obtained from patients to assess the reliability of a monoclonal (FemtoLab H. pylori) and a polyclonal (Premier Platinum HpSA) stool antigen test and to compare the diagnostic accuracies of these two tests. A chi2 test was used for statistical comparisons.

RESULTS

Using cut-off values of 0.19 for FemtoLab H. pylori and 0.16 for Premier Platinum HpSA, the sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy were 93%, 90%, 98%, 68% and 93% for the monoclonal test and 84%, 67%, 94%, 40% and 81% for the polyclonal test, respectively. The sensitivity, specificity, negative predictive value and diagnostic accuracy of the monoclonal test were significantly greater than those of the polyclonal test (chi2 = 3.98; p < .05 for sensitivity and chi2 = 15.67; p = .000 for specificity, chi2 = 15.78; p = .000 for negative predictive value and chi2 = 6.37; p = .012 for diagnostic accuracy). The bacterial load did not affect the sensitivity of either test.

CONCLUSIONS

The monoclonal FemtoLab H pylori test, using a cut-off 0.19, is a very sensitive, specific and easy to perform diagnostic tool for the primary diagnosis of H. pylori infection in Turkish patients with dyspepsia.