Comparison of three stool antigen tests in confirming Helicobacter pylori eradication in adults

Clinical Performance of the Automated LIAISON® Meridian H. pylori SA Stool Antigen Test

Background

Antigens derived from Helicobacter pylori can be used as stool biomarkers to assist in the diagnosis of H. pylori infection. Since current assays have variable performance, we assessed the clinical performance of the automated LIAISON® Meridian H. pylori infection. Since current assays have variable performance, we assessed the clinical performance of the automated LIAISON® Meridian

Methods

This prospective multisite study enrolled patients undergoing an esophagogastroduodenoscopy with collection of biopsy and stool specimens. Adult patients (≥22 years) participated in the study from February 2017 to August 2018. Specimens of the stomach were tested by three methods, known as the Composite Reference Method: (1) histological evaluation, (2) culture of the organism, and (3) rapid urease detection test. H. pylori infection. Since current assays have variable performance, we assessed the clinical performance of the automated LIAISON® Meridian H. pylori infection. Since current assays have variable performance, we assessed the clinical performance of the automated LIAISON® Meridian

Results

277 patients (63% female) were included in the study. The prevalence of infected subjects was 24.2% in this study cohort. Clinical performance assessed against the Composite Reference Method showed very good agreement (Cohen′s kappa = 0.922), with good sensitivity (95.5%) and specificity (97.6%). Reproducibility study results showed total imprecision ranging from 3.1% to 13.9% CV.

Conclusion

The automated LIAISON® Meridian H. pylori SA assay brings reliable noninvasive testing for H. pylori to the laboratory that is in very good agreement with the current, more invasive biopsy-based methods such as histology, culture, or rapid urease test. The clinical trial identifiers are NCT03060746 (pretherapy) and NCT03060733 (posttherapy).H. pylori infection. Since current assays have variable performance, we assessed the clinical performance of the automated LIAISON® Meridian H. pylori infection. Since current assays have variable performance, we assessed the clinical performance of the automated LIAISON® Meridian

Non-invasive tests for the diagnosis of helicobacter pylori: state of the art

Usually, non-invasive tests are the first methods for diagnosing Helicobacter pylori (HP) infection. Among these, serological test, stool antigen research and urea breath test are the most used. Antibodies anti-HP are not recommended in low prevalence population, moreover they cannot reveal an ongoing infection, but they only prove a contact with the bacterium. Also, they can persist for a long time after the eradication of the infection, therefore, they should not be used to verify the success of eradication therapy. Stool antigen research and Urea Breath Test (UBT) are useful both in diagnosis and during follow-up after eradication treatment. The stool antigen test is cheaper than Urea breath test with similar sensitivity and specificity. Non-invasive tests are not able to diagnose the associated complications to HP infection. (www.actabiomedica.it)

Non-invasive diagnostic tests for Helicobacter pylori infection

BACKGROUND

Helicobacter pylori (H pylori) infection has been implicated in a number of malignancies and non-malignant conditions including peptic ulcers, non-ulcer dyspepsia, recurrent peptic ulcer bleeding, unexplained iron deficiency anaemia, idiopathic thrombocytopaenia purpura, and colorectal adenomas. The confirmatory diagnosis of H pylori is by endoscopic biopsy, followed by histopathological examination using haemotoxylin and eosin (H & E) stain or special stains such as Giemsa stain and Warthin-Starry stain. Special stains are more accurate than H & E stain. There is significant uncertainty about the diagnostic accuracy of non-invasive tests for diagnosis of H pylori.

OBJECTIVES

To compare the diagnostic accuracy of urea breath test, serology, and stool antigen test, used alone or in combination, for diagnosis of H pylori infection in symptomatic and asymptomatic people, so that eradication therapy for H pylori can be started.

SEARCH METHODS

We searched MEDLINE, Embase, the Science Citation Index and the National Institute for Health Research Health Technology Assessment Database on 4 March 2016. We screened references in the included studies to identify additional studies. We also conducted citation searches of relevant studies, most recently on 4 December 2016. We did not restrict studies by language or publication status, or whether data were collected prospectively or retrospectively.

SELECTION CRITERIA

We included diagnostic accuracy studies that evaluated at least one of the index tests (urea breath test using isotopes such as 13C or 14C, serology and stool antigen test) against the reference standard (histopathological examination using H & E stain, special stains or immunohistochemical stain) in people suspected of having H pylori infection.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the references to identify relevant studies and independently extracted data. We assessed the methodological quality of studies using the QUADAS-2 tool. We performed meta-analysis by using the hierarchical summary receiver operating characteristic (HSROC) model to estimate and compare SROC curves. Where appropriate, we used bivariate or univariate logistic regression models to estimate summary sensitivities and specificities.

MAIN RESULTS

We included 101 studies involving 11,003 participants, of which 5839 participants (53.1%) had H pylori infection. The prevalence of H pylori infection in the studies ranged from 15.2% to 94.7%, with a median prevalence of 53.7% (interquartile range 42.0% to 66.5%). Most of the studies (57%) included participants with dyspepsia and 53 studies excluded participants who recently had proton pump inhibitors or antibiotics.There was at least an unclear risk of bias or unclear applicability concern for each study.Of the 101 studies, 15 compared the accuracy of two index tests and two studies compared the accuracy of three index tests. Thirty-four studies (4242 participants) evaluated serology; 29 studies (2988 participants) evaluated stool antigen test; 34 studies (3139 participants) evaluated urea breath test-13C; 21 studies (1810 participants) evaluated urea breath test-14C; and two studies (127 participants) evaluated urea breath test but did not report the isotope used. The thresholds used to define test positivity and the staining techniques used for histopathological examination (reference standard) varied between studies. Due to sparse data for each threshold reported, it was not possible to identify the best threshold for each test.Using data from 99 studies in an indirect test comparison, there was statistical evidence of a difference in diagnostic accuracy between urea breath test-13C, urea breath test-14C, serology and stool antigen test (P = 0.024). The diagnostic odds ratios for urea breath test-13C, urea breath test-14C, serology, and stool antigen test were 153 (95% confidence interval (CI) 73.7 to 316), 105 (95% CI 74.0 to 150), 47.4 (95% CI 25.5 to 88.1) and 45.1 (95% CI 24.2 to 84.1). The sensitivity (95% CI) estimated at a fixed specificity of 0.90 (median from studies across the four tests), was 0.94 (95% CI 0.89 to 0.97) for urea breath test-13C, 0.92 (95% CI 0.89 to 0.94) for urea breath test-14C, 0.84 (95% CI 0.74 to 0.91) for serology, and 0.83 (95% CI 0.73 to 0.90) for stool antigen test. This implies that on average, given a specificity of 0.90 and prevalence of 53.7% (median specificity and prevalence in the studies), out of 1000 people tested for H pylori infection, there will be 46 false positives (people without H pylori infection who will be diagnosed as having H pylori infection). In this hypothetical cohort, urea breath test-13C, urea breath test-14C, serology, and stool antigen test will give 30 (95% CI 15 to 58), 42 (95% CI 30 to 58), 86 (95% CI 50 to 140), and 89 (95% CI 52 to 146) false negatives respectively (people with H pylori infection for whom the diagnosis of H pylori will be missed).Direct comparisons were based on few head-to-head studies. The ratios of diagnostic odds ratios (DORs) were 0.68 (95% CI 0.12 to 3.70; P = 0.56) for urea breath test-13C versus serology (seven studies), and 0.88 (95% CI 0.14 to 5.56; P = 0.84) for urea breath test-13C versus stool antigen test (seven studies). The 95% CIs of these estimates overlap with those of the ratios of DORs from the indirect comparison. Data were limited or unavailable for meta-analysis of other direct comparisons.

AUTHORS' CONCLUSIONS

In people without a history of gastrectomy and those who have not recently had antibiotics or proton ,pump inhibitors, urea breath tests had high diagnostic accuracy while serology and stool antigen tests were less accurate for diagnosis of Helicobacter pylori infection.This is based on an indirect test comparison (with potential for bias due to confounding), as evidence from direct comparisons was limited or unavailable. The thresholds used for these tests were highly variable and we were unable to identify specific thresholds that might be useful in clinical practice.We need further comparative studies of high methodological quality to obtain more reliable evidence of relative accuracy between the tests. Such studies should be conducted prospectively in a representative spectrum of participants and clearly reported to ensure low risk of bias. Most importantly, studies should prespecify and clearly report thresholds used, and should avoid inappropriate exclusions.

Designing a novel ELISA method based on CagA, NapA recombinant antigens to increase sensitivity and specificity of Helicobacter pylori whole cell antigen detection

AIM

In this research, we designed a direct Enzyme Linked Immunoassay method to detect Helicobacter pylori antigens in stool specimens.

BACKGROUND

Helicobacter pylori infection as the worldwide problem is related to many gastrointestinal disorders such as gastritis, gastric cancer, non-ulcer disease, peptic ulcer disease and duodenal ulcer.

METHODS

We produced and purified recombinant CagA and NapA antigens in Escherichia coli and extracted their antibodies from a panel of positive sera specimens. We designed a novel enzyme linked immunoassay direct method in combination with the whole cell for the qualitative and quantitative detection of Helicobacter pylori antigens in human stool. Assay performance was evaluated by histopathology staining and urease activity.

RESULTS

The sensitivity and specificity of assay was determined as 91.7 [95% confidence interval: 89.3-95.6%] and 93.1% [95% CI: 91.2-96.4%], respectively. Novel ELISA exhibits enhanced sensitivity and specificity of Helicobacter pylori detection in comparison with another commercially available kit.

CONCLUSION

Combination of the recombinant antigens and whole cell of Helicobacter pylori in immunoassay designing is a new approach about early diagnosis, treatment and fallowing up of the Helicobacter pylori infected patients, especially in peptic cancer cases.

Evaluation of methods for H. pylori detection in PPI consumption using culture, rapid urease test and smear examination

BACKGROUND

Culture, rapid urease test (RUT) and smear examination have been used as reliable methods for diagnosis of H. pylori infection. Accurate performance of these tests requires good quality biopsies with considerable number of bacterial cells. However, consumption of proton pump inhibitors (PPIs) affects growth and urease activity of H. pylori, leading to false negative results. In this study the efficacy of culture, RUT and smear examination was assessed and the effect of PPI consumption was evaluated.

METHODS

Two antral biopsies from 530 dyspeptic patients with and without PPI consumption were used for RUT, culture and smear examination. Statistical analysis was used to determine the association between results of culture, RUT or smear examination and PPI consumption. Sensitivity and specificity of three tests were calculated by standard methods.

RESULTS

H. pylori infection was detected in 40% of patients by culture, 48.3% by RUT and 21.1% by smear examination and the overall detection rate was 54%. A strong correlation was found between PPI consumption and negative results of culture and RUT (P<0.05) but not smear examination. The sensitivity of RUT was reduced as a result of PPI consumption. This reduction was more profound in 1-hr RUT (92.2% to 74.4%) compared with 24-hr RUT (93.9% to 81.6%).

CONCLUSIONS

Prevalence of H. pylori was declined, compared with previous studies. This decrement could be due to false negative results of H. pylori diagnostic tests, among which culture and RUT are mostly affected by PPI. Accordingly, PPI consumption should be stopped before performance of endoscopy.

Stool antigen tests for the management of Helicobacter pylori infection

Stool antigen tests (SATs) are noninvasive diagnostic modules for Helicobacter pylori (H. pylori) infection. Two types of SATs exist for the diagnosis of H. pylori infection, one based on enzyme immunoassay (EIA) and another on immunochromatography (ICA). SATs do not require expensive chemical agents or specified equipment; hence, they are less expensive compared with the urea breath test. Both European and Japanese guidelines have shown that EIA-based SATs using monoclonal antibodies are useful for primary diagnosis as well as for the assessment of eradication therapy. ICA-based tests do not require particular equipment and are therefore useful in developing countries. SATs are also useful for the diagnosis of H. pylori infection in children and post gastric surgery patients. SATs performed via EIA can assess H. pylori infection in a large number of subjects, almost as well as serology. Thus, SATs would be useful or detecting current infection in such a survey to identify and eradicate H. pylori infection. The accuracy of SATs is lower when the stool samples are unformed or watery, because H. pylori-specific antigens in the stool samples are diluted. Temperature and the interval between stool sample collection and measurement also affect the results of SATs. The choice of test kit depends on the sensitivity and specificity in each region and the circumstances of each patient.

Managing dyspepsia in the young adult patient: effects of different tests for Helicobacter pylori in a "test-and-scope" approach

AIM

To evaluate how different methods for the detection of Helicobacter pylori influence on a "test, score and scope" decision approach in young dyspeptic patients.

RESULTS

Complete data from 341 patients (52.2% males) were analyzed. One hundred and ten (32%) were H. pylori-positive by definition. The rapid serology test was true-positive in 64 patients, false-positive in 8, and false-negative in 46. For the EIA IgG serology test, the corresponding results were 99 true-positive, 7 false-positive, and 11 false-negative. If the H. pylori fecal test or urea breath test had been applied, 108 (98%) and 107 (97%) positives would have been correctly detected, respectively, as well as 14 and 7 false positives. Models using test data in a setting of decreasing H. pylori prevalence show that test properties have increasing significance.

CONCLUSIONS

In a selection strategy for young dyspeptics based on the detection of H. pylori, the choice of test should be made with caution. H. pylori fecal test would probably give the best basis for such selection.

Characterization and usefulness of stool antigen tests using a monoclonal antibody to Helicobacter pylori catalase

BACKGROUND AND AIM

Two types of stool antigen tests have been used in the management of Helicobacter pylori infection. Testmate Pylori Antigen enzyme immunoassay (TPAg EIA) is a direct sandwich enzyme immunoassay (EIA) while Testmate Rapid Pylori Antigen (Rapid TPAg) is performed using immunochromatography. The aim of this study was to study the characterization and usefulness of these tests.

METHODS

Accuracy of both tests was studied using 111 fecal samples obtained from H. pylori-positive or -negative patients. Cross-reactivity was examined with four other Helicobacter spp. and five fecal bacteria in humans. To estimate the sensitivity of both kits, we tested H. pylori clinical strains. We also examined the diagnostic performances of both tests after the storage for 12 months.

RESULTS

The accuracy of both Testmate kits was 100% in fecal samples from 111 patients. No cross-reactivity was observed in both Testmate kits in five fecal bacteria and four other Helicobacter spp. TPAg EIA and Rapid TPAg showed positive results in 1342 of 1344, and 483 of 485 clinical strains, respectively. Diagnostic performances was maintained for 12 months when TPAg EIA was stored at 4°C and Rapid TPAg at 30°C.

CONCLUSIONS

We examined the details of high accuracy of TPAg EIA and Rapid TPAg. The diagnostic performance of both kits was maintained after storage for up to 1 year. The two types of tests would be useful in the management of H. pylori infection.

Comparison of monoclonal antibody-based stool antigen tests to determine the results of Helicobacter pylori eradication therapy

OBJECTIVE

Stool antigen tests using monoclonal antibody are used to test the results of eradication therapy of Helicobacter pylori. A newly developed test using multiple monoclonal antibodies is considered to have higher sensitivity. The aim of this study was to examine whether monoclonal antibody-based stool antigen tests are equally applicable to determine the results of eradication therapy.

MATERIALS AND METHODS

Stool specimens obtained from patients infected with H. pylori were diluted by human stool and tested by both Testmate pylori antigen enzyme immunoassay (TPAg EIA) and Premier Platinum HpSA PLUS (HpSA ELISA II). A total of 239 patients infected with H. pylori received eradication therapy and 5-8 weeks after finishing the treatment, stool samples were tested by TPAg EIA and HpSA ELISA II. On the same day of stool collection, all the patients received (13)C-urea breath test (UBT).

RESULTS

After 5× dilution, optical density (OD) values of TPAg EIA were significantly reduced and three out of four stool specimens were tested negative after 10× dilution. By contrast, three specimens were tested positive even after 100× dilution by HpSA ELISA II. In the determination of eradication therapy, accordance between the two tests was 95.8%. Among 199 patients who tested negative by both stool antigen tests, 10 patients were positive by UBT. Overall accordance of TPAg EIA and HPSA ELISA II to UBT was 91.2% and 95.4%, respectively (NS).

CONCLUSIONS

Although reduction of OD values was seen in TPAg EIA, it did not seem to cause false negative results in stool samples after eradication therapy. Both TPAg EIA and HpSA ELISA II were equally useful to determine the results of eradication therapy comparing with UBT.

Accuracy of monoclonal stool tests for determining cure of Helicobacter pylori infection after treatment

BACKGROUND

Studies comparing new monoclonal fecal tests for evaluating cure of Helicobacter pylori infection after treatment are scarce. The objective was to compare the diagnostic accuracy of three monoclonal stool tests: two rapid in-office tools -RAPID Hp StAR and ImmunoCard STAT! HpSA - and an EIA test - Amplified IDEIA Hp StAR.

MATERIALS AND METHODS

Diagnostic reliability of the three tests was evaluated in 88 patients at least 8 weeks after H. pylori treatment. Readings of immunochromatographic tests were performed by two different observers. Sensitivity, specificity, positive and negative predictive values and 95% confidence intervals were calculated.

RESULTS

All tests presented similar performance for post-eradication testing. Sensitivity for detecting persistent infection was 100% for both Amplified IDEIA and RAPID Hp StAR and 90% for ImmunoCard STAT! HpSA. Respective specificities were 94.9%, 92.3-93.6% and 94.9%. Negative predictive values were very high (100%, 100% and 98.7% respectively). But positive predictive values were lower, ranging from 62.5 to 71.4%.

CONCLUSION

All monoclonal fecal tests in this series presented similar performance in the post-treatment setting. A negative test after treatment adequately predicted cure of the infection. However, nearly a third of tests were false positive, showing a poor predictive yield for persistent infection.

A "screen-and-treat" approach for Helicobacter pylori infection: a population-based study in Vammala, Finland

BACKGROUND

To accelerate the decline of Helicobacter pylori infection, and to study the significance of the possible risk factors for H. pylori infection in Finland, we started a voluntary H. pylori"screen-treat-retest-and-retreat" program for all young adults at primary health care in Vammala, Finland after a pilot study in 1994 including 504 subjects aged 15-75.

MATERIALS AND METHODS

A total of 3326 aged 15-40 in 1996, and 716 aged 15 and 584 aged 45 in 1997-2000 were screened for H. pylori using serology. Helicobacter pylori positive were treated, cure was verified by serology.

RESULTS

The eradication rates were 93.8%, 82.2%, and 77.6% per protocol in pilot study in 1994, in subjects invited in 1996 and 1997-2000, respectively. Helicobacter pylori seroprevalence rates were calculated to have decreased from 36% to 14% in pilot study, from 12% to 4% among subjects invited in 1996, from 3% to 2% among subjects aged 15 and from 27% to 12% among subjects aged 45 in 1997-2000. An epidemiologic questionnaire in 1996 revealed that crowding in the childhood household, low education of the mother, current smoking and alcohol consumption, unfavorable housing conditions, and sick leaves due to dyspepsia were independently associated with H. pylori infection.

CONCLUSIONS

This intervention with high participation rates resulted in a significant decline in calculated H. pylori seroprevalence rates. Although the low prevalence of H. pylori infection may limit the cost efficiency of the program, the intervention is expected to reduce the burden of H. pylori-associated diseases.

Helicobacter pylori: diagnosis and treatment

PURPOSE OF REVIEW

Multiple diagnostic methods and treatment strategies have been developed to detect and treat the Helicobacter pylori infection. Many of them have stood the test of time; others lost their value with the introduction of new test and treatment modalities. This review focuses on the current diagnostic methods and their clinical implications, as well as on established and novel treatment strategies.

RECENT FINDINGS

The increasing antimicrobial resistance has resulted in a decline of the success rate of recommended eradication regimens. The current guidelines recommend as first-line treatment clarithromycin, amoxicillin or metronidazole, and proton pump inhibitor twice daily, but recent studies have demonstrated an increasing eradication failure with these regimens. Several treatment modifications have been adopted regarding duration and combination of substances.

SUMMARY

The currently recommended first-line treatments are effective and well tolerated. In areas with high antimicrobial resistance rates, new antibiotic combinations and modifications in the sequence of drug administration are proposed as alternative treatment options to standard triple therapy. Future treatment strategies have to focus on regional antimicrobial resistance adopted treatment selection and the development of new antibiotics.

Evaluation of a latex agglutination test (PYLOGEN) for the detection of Helicobacter pylori in stool specimens

The aim of the study was to assess a new latex agglutination (LA) stool antigen assay (PYLOGEN; CerTest Biotec, Zaragoza, Spain) in the diagnosis of Helicobacter pylori infection and to monitor its eradication after treatment. The LA test has been approved for sale in Europe, and its approval from the US Food and Drug Administration is still pending. The individuals enrolled were classified into 3 groups of patients: Group 1 consisted of 38 patients who are H. pylori positive. The diagnosis of H. pylori infection was established if there was concordance between 2 test results (urea breath test [UBT], rapid urease test, and histopathologic study) or if the culture alone was positive. Patients with only 1 positive test were considered indeterminate and were excluded from the study. Group 2 comprised 9 patients without positive tests and who were considered to be H. pylori negative. Group 3 consisted of 57 patients who received eradication treatment. The sensitivity and specificity of the test were 78.9% and 100%, respectively. The results of the UBT of the patients were studied 6 weeks after eradication therapy. The sensitivity and specificity of the LA test relative to UBT for patients after treatment were 75% and 93.3%, respectively.

Diagnostic accuracy of a rapid fecal test to confirm H pylori eradication after therapy: Prospective comparison with a laboratory stool test

AIM: To investigate the clinical performances of rapid stool test (ImmunoCard STAT HpSA, Meridian Diagnostic Inc.) in the evaluation of eradication therapy of H pylori and to compare it with a well-known and validated laboratory stool test (Amplified IDEA Hp StAR, Dako).

METHODS: Stool samples of 122 patients were evaluated after eradication therapy of H pylori. H pylori status was assessed by 13C-urea breath test (UBT). Stool specimens were tested using either the rapid immunoassay kit or the laboratory immunoassay kit.

RESULTS: Forty-three patients were infected and 79 non-infected. Sensitivity and specificity of ImmunoCard STAT and Hp StAR were 58.14% and 76.4%, and 97.47% and 98.73%, respectively (P > 0.05). Overall agreement between the two tests was 92.6% (113 of 122 cases).

CONCLUSION: ImmunoCard STAT seems to have rather low performances, and it cannot be regarded as a reliable tool in the post-treatment setting. Also Hp StAR cannot be recommended to confirm H pylori eradication after treatment.

Immunochromatographic monoclonal test for detection of Helicobacter pylori antigen in stool is useful in children from high-prevalence developing country

BACKGROUND

Tests to detect Helicobacter pylori antigens in feces for diagnosis of infection in children demonstrate controversial results. One novel and fast monoclonal test improves diagnostic accuracy in adults, but clinical evidence of its usefulness at pediatric age is insufficient to date. The objective of this work was to evaluate the diagnostic accuracy of this test in a sample of Mexican children.

METHODS

We conducted a transversal study in 150 selected children with digestive symptoms suggestive of organic disease in whom a clinical history was conducted in addition to a fast monoclonal test (ImmunoCardSTAT HpSA, Meridian Diagnostics) performed by immunochromatography. Patients were submitted to endoscopy and histopathologic study.

RESULTS

Of the 150 children (mean age 7.8 +/- 4.7 years), 107 (71.3%) were positive for the test, and presence of H. pylori was confirmed histologically in 109 (72.7%) children, with sensitivity of 96.3% (95% CI = 95.8-96.8), specificity of 95.1% (95% CI = 93.9-96.4), and accuracy of 96.0% (95% CI, -95.6 to -96.3); pretest probability was 0.73, while post-test probability was 0.98. Infection rate and test accuracy increased with age.

CONCLUSIONS

This test is useful for detecting H. pylori infection in children of all ages, and is a good alternative for screening studies in developing countries with elevated prevalence, due to its being fast, noninvasive, inexpensive, and easy to carry out.

Comparison of stool enzyme immunoassay and immunochromatographic method for detecting Helicobacter pylori antigens before and after eradication

The objective of this study is to compare the performance of enzyme immunoassay (Premier Platinum HpSA) and immunochromatographic method (ImmunoCard HpSA STAT) in detecting stool Helicobacter pylori antigen before and after eradication therapy. Two hundred forty dyspeptic patients (143 men and 97 women; mean age, 53.2 years old; range, 19-79 years old) volunteered to participate in this study. Those who delivered improper stool samples, including diarrhea, inadequate amount, or delayed delivery after collection, were excluded. All of the participants received endoscopy, biopsy-based tests, and noninvasive tests, including (13)C-urea breath test ((13)C-UBT) and 2 stool antigen tests. Fifty-eight patients completed all the above tests before and after eradication therapy, and each contributed to 2 person-times. In total, there were 176 person-times in the preeradication group and 100 in the posteradication group that were analyzed for comparison. Follow-up endoscopic examinations were done 2 to 4 months after completion of eradication therapy, and stool samples were collected within 3 days after endoscopy. Positive H. pylori infection was established when either culture was positive or any 2 of the histology, rapid urease test, and UBT were positive. In the preeradication group (n = 176), 99 (56.3%) were H. pylori positive and 77 were Hp negative. In the posteradication group (n = 100), the treatment was successful in 67 (67.0%) of them. In the preeradication group, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were 95.2%, 87.0%, 90.4%, 93.1%, and 91.5%, respectively, for ImmunoCard HpSA STAT, and 83.8%, 90.9%, 92.2%, 81.4%, and 86.9%, respectively, for Premier Platinum HpSA. In the posteradication group, the sensitivity, specificity, PPV, NPV, and accuracy were 100%, 91.0%, 84.6%, 100%, and 94.0%, respectively, for ImmunoCard HpSA STAT, and 84.9%, 92.5%, 84.8%, 92.5%, and 90.0%, respectively, for Premier Platinum HpSA. There were no statistically significant differences between these 2 stool tests. ImmunoCard HpSA STAT is a rapid, simple, and accurate in-clinic test for preeradication diagnosis of H. pylori and posteradication follow-up.

Detection of Helicobacter species in chronic liver disease and chronic inflammatory bowel disease

AIM

To study the association between helicobacters and chronic liver diseases and chronic inflammatory bowel diseases.

PATIENTS AND METHODS

Thirty-two patients with various chronic liver diseases and 137 patients with inflammatory bowel disease were enrolled. Antibodies to H. pylori, H. hepaticus, H. bilis, and H. pullorum were measured by enzyme immunoassay (EIA), and sera positive in a non-pylori helicobacter EIA were further examined by immunoblot assay. Detection of Helicobacter DNA in liver biopsies was done by denaturating gradient gel electrophoresis of PCR products (PCR-DGGE) and DNA sequence analysis.

RESULTS

Six inflammatory bowel disease patients, four with ulcerative colitis and two with Crohn's disease, and one liver disease patient with autoimmune cholangitis had antibodies to non-pylori helicobacters by an immunoblot assay. Four immunoblot assay-negative patients, three with autoimmune and one with non-autoimmune liver disease, had Helicobacter DNA in liver biopsies; three of the polymerase chain reaction (PCR) products were closely related to non-pylori helicobacters.

CONCLUSION

Evidence for non-pylori helicobacters was scant in Finnish patients with inflammatory bowel disease or chronic but not end stage liver disease. We cannot, however, rule out their role in these diseases.

The clinical applications and accuracy of 2 rapid near-patient tests in detecting Helicobacter pylori infection

Noninvasive methods for assessing Helicobacter pylori infection status are now an integral part of managing patients with upper gastrointestinal complaints. The aim of this study is to evaluate the feasibility and diagnostic accuracy of 2 rapid tests: a urine-based H. pylori antibody detection method (Rapirun) and a stool-based H. pylori antigen detection method (immunocard STAT! HpSA). The combined use of the mentioned 2 tests was also evaluated, which has not been described in previous similar studies. Urine and stool specimens were collected from patients who were arranged for gastroendoscopic examination. The urine and stool specimens were tested with Rapirun and immunocard STAT! HpSA separately. The estimated reaction time was about 15 to 20 min for the former and 5 to 10 min for the latter. H. pylori infection was confirmed with 4 tests: culture, histology, rapid urease test, and the (13)C-urea breath test. Obtained results from both kits were compared with confirmed results. One hundred twenty patients were eligible for analysis. Of them, 62 tested positive for H. pylori infection and 58 were negative by the confirmation criteria. The urine Rapirun test relative to the confirmed results showed sensitivity, specificity, and accuracy as 87.1% (confidence interval [CI] = 81.1-93.1%), 89.7% (CI = 84.2-95.1%), and 88.3%, respectively. The stool immunocard STAT! HpSA test relative to the confirmed results showed sensitivity, specificity, and accuracy as 96.8% (CI = 93.6-99.9%), 82.8% (CI = 76.0-89.5%), and 90%, respectively. The combined-use method of both tests revealed sensitivity, specificity, and accuracy as 98.4% (CI = 96.1-100%), 81.0% (CI = 74.0-88.1%), and 90%, respectively. These 2 urine and stool tests have a satisfactory accuracy around 90% in detecting H. pylori infection. In consideration of the advantages of cheapness, timesaving, and ease of use, both can be used as rapid near-patient tests in general practice. The combined use of both tests was also promising in detecting H. pylori infection.

Diagnosis of Helicobacter pylori infection

A growing interest in non-invasive tests for the detection of Helicobacter pylori has been observed recently, reflecting a large number of studies published this year. New tests have been validated, and the old ones have been used in different clinical situations or for different purposes. Stool antigen tests have been extensively evaluated in pre- and post-treatment settings both in adults and children, and the urea breath test has been studied as a predictor of bacterial load, severity of gastric inflammation, and response to eradication treatment. Several studies have also explored the usefulness of some serologic markers as indicators of the gastric mucosa status. With regard to invasive tests, molecular methods are being used more and more, but the breakthrough this year was the direct in vivo observation of H. pylori during endoscopy.

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.

Stool antigen tests for the detection of Helicobacter pylori in children

Stool specimens from 102 children (median age = 6.0 years; Helicobacter pylori in biopsy specimens, n = 43) were tested for H. pylori with the monoclonal antibody-based enzyme immunoassay HpStar. In 28 cases, the specimen was obtained with a rectal cotton swab during endoscopy. The sensitivity and specificity of the HpStar were 0.95 and 0.90, respectively, as compared with biopsy-based methods. The rectal cotton swab specimen gave accurate results in 24 of the 28 cases. Storage of specimens for 1, 3, or 7 days (n = 6) had a minor effect on the results, but one specimen's originally positive value on borderline turned negative when it was kept in room temperature. Forty-eight specimens were tested in parallel with all 3 tests used: HpStar, Premium Platinum HpSA, and the rapid test ImmunoCardSTAT! The accuracy rates of the tests were 98% for the HpSA and HpStar and 96% for the ImmunoCardSTAT! The performance of the stool antigen tests was excellent in young children.

Stool antigen tests in the diagnosis of Helicobacter pylori infection before and after eradication therapy

AIM

To evaluate two enzyme immunoassay-based stool antigen tests, Premier Platinum HpSA and Amplified IDEIA HpStAR, and one rapid test, ImmunoCard STAT! HpSA, in the primary diagnosis of Helicobacter pylori (H pylori) infection and after eradication therapy.

METHODS

Altogether 1 574 adult subjects were screened with a whole-blood H pylori antibody test and positive results were confirmed with locally validated serology and (13)C-urea breath test. All 185 subjects, confirmed to be H pylori positive, and 97 H pylori-negative individuals, randomly selected from the screened study population and with negative results in serology and UBT, were enrolled. After eradication therapy the results of 182 subjects were assessed.

RESULTS

At baseline, the sensitivity of HpSA and HpStAR was 91.9% and 96.2%, respectively, and specificity was 95.9% for both tests. ImmunoCard had sensitivity of 93.0% but specificity of only 88.7%. After eradication therapy, HpSA and HpStAR had sensitivity of 81.3% and 100%, and specificity of 97.0% and 97.6%, respectively. ImmunoCard had sensitivity of 93.8% and specificity of 97.0%. HpSA, HpStAR, and ImmunoCard had PPV 77%, 80%, and 75%, and NPV 98%, 100%, and 99%, respectively.

CONCLUSION

In primary diagnosis, the EIA-based tests performed well. After eradication therapy, negative results were highly accurate for all the three tests. HpStAR had the best overall performance.