Stool antigen tests for the detection of Helicobacter pylori in children

Aiding gastrointestinal diagnostic laboratory by designing a device for the non invasive detection of peptic ulcer

Peptic ulcer (PU) has been recognized as an utmost gastrointestinal problem that affects the lining of the stomach and duodenum, specifically triggering soreness. It is a life-threatening condition, while roots of the infection are not identified yet. There are various risk factors for the cause of peptic ulcer disease, but the most significant is "Helicobacter pylori" (H. pylori). The detection of this disease involves different invasive procedures which are painful and not feasible for everyone. The aim of this device is to identify the peptic ulcer non-invasively by unmasking the presence of H. Pylori bacterium by monitoring crucial parameters of the disease which include respiration rate, heart rate, ECG, pH of Saliva, and temperature. Multiple investigations related to PU authenticate the alteration in these physicochemical aspects of the body. The increase in the level of stomach acid in PU is responsible for belching and bloating. Heart rate, temperature, and respiratory rate are also elevated during peptic ulcers while the pH of Saliva is decreased toward the acidic side. The disturbance in the QRS complex of the ECG wave is also observed. These biosignals are examined as analog input from the body, sent into MCP3008, and converted into digital input signals. Then these digital inputs are directed toward Raspberry pi 3 which processes, received inputs, and shows output on the LCD. The values of parameters obtained are then compared with standard values and a conclusion is made that whether a patient has a peptic ulcer or not.

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.

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.

Prevalence of Helicobacter pylori infection among preschool children in Latvia: no significant decrease in prevalence during a ten year period

Aims: Published data show a trend of decreasing prevalence of Helicobacter pylori in Eastern European countries due to socioeconomic changes. The aim of this study was to determine the prevalence of H. pylori infection among children in Latvia and to compare these results with previous studies in the same population. The risk factors associated with infection were also analysed. Methods: Preschool children in kindergartens and primary health care centres were investigated using a stool antigen test. Their parents were asked to fill out a questionnaire about possible risk factors. Statistical analysis included Pearson’s χ2 test and linear regression analysis. Results: The prevalence of H. pylori infection determined by the monoclonal stool antigen test in children aged 1–6 years (median 5 years) was 15.5% (15/101) (95% confidence interval 8.67–23.48%). In the regression analysis, H. pylori positivity was significantly negatively associated with the consumption of imported fruit at least once per week ( p=0.02). Conclusions: The prevalence of H. pylori in the studied population has not decreased significantly during the last decade and is still associated with socioeconomic factors. The role of some dietary factors (e.g. the consumption of fruit) in the spread of infection should be studied further.

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.

Accuracy of stool antigen test for the diagnosis of Helicobacter pylori infection in children: a meta-analysis

INTRODUCTION

Helicobacter pylori (H. pylori) is regarded as a major pathogen in gastrointestinal diseases and the infection rate is still at a high level in children. Therefore, the diagnosis is of great clinical importance. The objective was to perform a meta-analysis on H. pylori stool antigen test (SAT) for the diagnosis of the infection in children.

METHODS

Published information on the sensitivity and specificity of stool antigen test in each study was collected to assess the accuracy of the test for the diagnosis of H. pylori infection. Forty-five eligible studies were selected for analysis. Data on the publication year, H. pylori prevalence, eradication rate and gold standard of each study were summarized.

RESULT

Forty-five studies, including 5931 patients, evaluated the accurancy of H. pylori SAT. Pooled sensitivity, specificity, LR+ and LR- were: 92.1%, 94.1%, 17.01, 0.085, respectively. Subgroup analyses were conducted to evaluate the sensitivity and specificity of H. pylori SAT in different situations and found that sensitivity and specificity were significantly higher when monoclonal H. pylori SAT and two or more reference methods were used.

CONCLUSIONS

Detection of H. pylori antigen in stools with ELISA monoclonal antibodies is a non-invasive efficient test for the diagnosis of infection in children. However, the available one-step and polyclonal SAT tests are still unreliable.

Evaluation of an Iranian Home-made Helicobacter pylori Stool Antigen ELISA Kit

Background:

Current diagnosis of Helicobacter pylori infection by biopsy-based tests requires invasive sampling. Non-invasive methods such as the H. pylori stool-antigen (HpSA) test may be the best alternative for diagnosis of active infection. However, due to the presence of antigenic-diversity among the strains, various commercial tests have shown some discrepancies in different geographical-areas.

Objectives:

This study evaluates a homemade HpSA kit developed by using the H. pylori antigens from Iranian-isolates for detection of H. pylori in the stool of infected patients.

Patients and Methods:

Based on the endoscopic features and/or a rapid-urease test (RUT), 30 child and 50 adult patients, were recruited. From these candidates, three biopsies for RUT, culture and histology, and a stool-sample, were obtained. Patients were considered as H. pylori-positive if culture alone or RUT plus histology were found to be positive. Presence of H. pylori antigens in their stools was detected by the homemade HpSA test and an imported HpSA kit (Immundiagnostik, Germany).

Results:

Using the biopsy-based tests with RUT, histology and culture, 53% (16/30) of children were diagnosed as H. pylori–positive while using the imported kit 57% and the homemade kit 50% of the candidates showed positive results. Also by the biopsy-based tests, 54% of the adults were diagnosed as H. pylori-positive while by the homemade kit 56% showed positive results. Considering the biopsy-based tests as the gold standard, sensitivity and specificity for the imported kit was 94% and 86%, respectively, while the mean sensitivity and specificity for the homemade kit was 96% and 98%, respectively.

Conclusions:

The homemade kit, compared with the imported kit and biopsy-proven tests may be a valid and reliable method for determining the presence of H. pylori infection in Iran.

Helicobacter pylori infection in infants and toddlers in South America: concordance between [13C]urea breath test and monoclonal H. pylori stool antigen test

Accurate noninvasive tests for diagnosing Helicobacter pylori infection in very young children are strongly required. We investigated the agreement between the [(13)C]urea breath test ([(13)C]UBT) and a monoclonal ELISA (HpSA) for detection of H. pylori antigen in stool. From October 2007 to July 2011, we enrolled 414 infants (123 from Brazil and 291 from Peru) of ages 6 to 30 months. Breath and stool samples were obtained at intervals of at least 3 months from Brazilian (n = 415) and Peruvian (n = 908) infants. [(13)C]UBT and stool test results concurred with each other in 1,255 (94.86%) cases (kappa coefficient = 0.90; 95% confidence interval [CI] = 0.87 to 0.92). In the H. pylori-positive group, delta-over-baseline (DOB) and optical density (OD) values were positively correlated (r = 0.62; P < 0.001). The positivity of the tests was higher (P < 0.001; odds ratio [OR] = 6.01; 95% CI = 4.50 to 8.04) in Peru (546/878; 62.2%) than in Brazil (81/377; 21.5%) and increased with increasing age in Brazil (P = 0.02), whereas in Peru it decreased with increasing age (P < 0.001). The disagreement between the test results was associated with birth in Brazil and female gender but not with age and diarrhea. Our results suggest that both [(13)C]UBT and the stool monoclonal test are reliable for diagnosing H. pylori infection in very young children, which will facilitate robust epidemiological studies in infants and toddlers.

Assessment of systemic matrix metalloproteinase and their regulator response in children with Helicobacter pylori gastritis

BACKGROUND

Helicobacter pylori causes gastritis and is the most important risk factor of peptic ulcer disease and gastric cancer. In chronic adulthood H. pylori infection some matrix metalloproteinases (MMPs), which are proteolytic metalloendopeptidases regulated by tissue inhibitors of metalloproteinases (TIMPs), are upregulated. Our aim was to determine circulating levels of MMPs and their regulators TIMP-1, human neutrophil elastase (HNE) and myeloperoxidase (MPO) in childhood H. pylori infection.

DESIGN AND METHODS

Twenty-six H. pylori positive and 34 H. pylori negative children whose H. pylori status was verified by histological examination of gastric biopsies were included. Serum samples were analysed by enzyme-linked immunosorbent assay.

RESULTS

Significantly decreased serum levels of TIMP-1 were detected in H. pylori-infected children (median, 97.50 ng/mL) as compared to H. pylori-negative children (median, 118.5 ng/mL, p = 0.003). However, there were no significant differences in serum levels of MMP-2, -7, -8, -9, and their regulators HNE and MPO between H. pylori-positive and -negative children.

CONCLUSIONS

Differing from the recent findings in adulthood H. pylori infection, only circulating TIMP-1 levels were significantly different between H. pylori-positive and -negative children. Whether this reflects the first sign of a proteolytic cascade later leading to increased levels of MMPs remains to be shown.

Helicobacter pylori diagnostic tests in children: review of the literature from 1999 to 2009

The array of tests that can be used for diagnosis of Helicobacter pylori infection is large, and it can be confusing to define which test to use particularly in children where results may not be comparable to those obtained in adult patients. Using PubMed, we reviewed the English literature from January 1999 to May 2009 to identify articles that determined sensitivity and specificity of H. pylori invasive and non-invasive diagnostic tests in children. We excluded articles that presented a review of the literature, abstracts, case reports, or series where children's results could not be separated from adult populations. Of the tissue based methods, rapid urease tests have better sensitivity than histology to detect presence of H. pylori; however, histology can detect the pathology associated with disease including gastritis, intestinal metaplasia, and other conditions that could be the cause of the child's symptoms. Culture of gastric tissues or stool has 100% specificity but sensitivity is low. Of the serologic tests, immunoblot has the best sensitivity. The urea breath tests have >75% sensitivity for detection of H. pylori before and after treatment. Immunoassays in stool using monoclonal antibodies have >95% sensitivity for detection of H. pylori before and after treatment. PCR testing can be performed in tissue and stool samples and can detect genes associated to antibiotic resistance. In summary, the current commercial non-invasive tests have adequate sensitivity and specificity for detecting the presence of H. pylori; however, endoscopy with histopathology is the only method that can detect H. pylori and lesions associated with the infection.

Diagnosis of Helicobacter pylori infection in a high-prevalence pediatric population: a comparison of 2 fecal antigen testing methods and serology

OBJECTIVES

Accurate methods for diagnosing active Helicobacter pylori infection in children have been limited to invasive or time-consuming techniques. Recently, fecal antigen testing has been used successfully for the diagnosis of H pylori infection in the pediatric population. We compared 2 monoclonal fecal antigen diagnostic methods in a population of children with a suspected high prevalence of H pylori infection. We also assessed the diagnostic performance of H pylori immunoglobulin G serology.

MATERIALS AND METHODS

In a cross-sectional study of African refugee children (<16 years) we compared an immunochromatographic technique (ICT) and serology with a monoclonal fecal antigen enzyme immunoassay (MFAT) method for the detection of active H pylori infection. Following the manufacturer's instructions, an optical density of >or=0.190 was used as a cutoff for MFAT. Sensitivity, specificity, and positive and negative predictive values were calculated.

RESULTS

Of the 193 eligible children enrolled, active H pylori infection was detected in 149 of 182 (81.9%) in whom MFAT was performed. The prevalence of active infection increased with age; children with active infection were significantly older, and there were no sex differences. ICT and serology underperformed in comparison with MFAT (ICT sensitivity 74.6%, specificity 63.6%, positive predictive value 89.8%, negative predictive value 36.8%; and serology sensitivity 57.9%, specificity 77.4%, positive predictive value 92.0%, negative predictive value 29.9%).

CONCLUSIONS

Monoclonal enzyme immunoassay fecal antigen testing is a practical and feasible alternative to traditional invasive diagnostic methods in high-prevalence pediatric populations. Neither immunochromatography nor serology is useful for the diagnosis of active H pylori infection in these children.

Helicobacter pylori stool antigen (HpSA) tests in children before and after eradication therapy: comparison of rapid immunochromatographic assay and HpSA ELISA

The rapid immunochromatography for Helicobacter pylori (H. pylori) stool antigen (rapid HpSA) test is a recently-developed method for detection of H. pylori infection. The objective of this study was to assess the pre and post-eradication diagnostic accuracy of the rapid HpSA test compared with the conventional HpSA immunoassay (HpSA ELISA) in children. Sensitivity, specificity, positive predictive value, and negative predictive value for the rapid HpSA test were 94.6, 98.4, 94.6, and 98.4%, respectively, and those for the HpSA ELISA were 94.6, 96.1, 87.5, and 98.4%, respectively. No significant difference was observed between the sensitivity and specificity of the two HpSA tests in children (P = 1.000 and P = 0.250) or the sensitivity and specificity of the two HpSA tests pre and post-eradication therapy (P = 1.000 and P = 1.000). The rapid HpSA and HpSA ELISA are reliable methods of detection of H. pylori infection in the pediatric population before and after eradication therapy.

Evaluation of a novel monoclonal-based antigen-in-stool enzyme immunoassay (Premier Platinum HpSA PLUS) for diagnosis of Helicobacter pylori infection in Vietnamese children

BACKGROUND

Helicobacter pylori infection is difficult to diagnose in children, especially in developing countries where noninvasive methods such as urea breath test are often not available. We evaluate the sensitivity and specificity of a new monoclonal antibody-based antigen-in-stool enzyme immunoassay (Premier Platinum HpSA PLUS) for diagnosis of H. pylori infection in Vietnamese children.

MATERIALS AND METHODS

Sensitivity of the antigen-in-stool test was evaluated in 232 children, 3-15 years of age, who were positive for H. pylori infection by culture from biopsies. For evaluation of the specificity 98 children of similar age with nongastrointestinal conditions and who were negative for H. pylori infection by serologic assays were included with blood and stool samples.

RESULTS

Of the 232 culture-positive children, 224 were also positive by Premier Platinum HpSA PLUS. Of the 98 control children, 93 were H. pylori negative also in the stool test. The sensitivity of Premier Platinum HpSA PLUS was thus 96.6% (95% CI 93.3-98.5) and the specificity was 94.9% (95% CI 88.5-98.3).

CONCLUSIONS

The findings have demonstrated Premium Platinum HpSA PLUS to be a reliable method for detection of H. pylori infection also in children in our area.

Diagnosis of Helicobacter pylori

Although there are attempts to perform Helicobacter pylori diagnosis directly in vivo using magnification endoscopy, most articles on diagnosis this year concerned non-invasive tests and molecular methods. For urea breath tests, there are attempts to have a quicker and cheaper test and to evaluate its role in cases of premalignant lesions. For stool antigens tests, evaluation of kits using monoclonal antibodies was carried out. Molecular tests have been applied for typing and detection of resistant mutants.

Helicobacter pylori infection in pediatrics

During the last year, epidemiologic studies have shown that spontaneous clearance of Helicobacter pylori infection has a less significant role in countries with high prevalence and, in contrast to adults, there is no male predominance of H. pylori infection in children. Early acquisition of H. pylori may play a role in the development of recurrent abdominal pain in children less than 5 years of age. In this very young age group, the adequate performance of stool antigen test and (13)C urea-breath test demonstrated satisfactory sensitivity and specificity as non-invasive methods to diagnose H. pylori infection. In the current paper, the most relevant pediatric studies on H. pylori infection published between April 2006 and March 2007 are reviewed.

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.

Evaluation of a novel rapid one-step monoclonal chromatographic immunoassay for detection of Helicobacter pylori in stool from children

A new rapid office-based one-step monoclonal immunoassay (RAPID Hp StAR, DakoCytomation, Cambridge, UK) for detection of Helicobacter pylori antigen in stool was evaluated in children against invasive diagnostic methods and compared to the results of a monoclonal EIA targeting the same antigen (Amplified IDEIA Hp StAR, DakoCytomation, Cambridge, UK). Coded stool samples from 118 symptomatic children (0.3-18.8 years) were investigated prior to any anti-H. pylori therapy. Fifty-four children were H. pylori infected defined by positive culture and/or two other positive tests ((13)C-urea breath test, histology, rapid urea test), the remaining 64 children showed concordant negative results. Thirty-four infected children (4.8-17.8 years) were monitored with (13)C-urea breath test (five remained positive) and stool test 6-8 weeks after anti-H. pylori therapy. The immunoassays were independently read by two investigators. The monoclonal EIA showed excellent sensitivity and specificity before (98% and 100%, respectively) and after therapy (100%; 96.2%). The rapid immunoassay was invalid for technical reasons in nine samples (5.9%). The two observers agreed in 31 positive and 93 negative results, but had discordant results in 17 samples (11.2%). Overall, the rapid test showed a poor sensitivity (63.8%-71.1%), but a good specificity (91.1%-96.2%) before treatment. We conclude that the new office based monoclonal enzyme immunoassay for diagnosis of H. pylori should be modified to improve sensitivity, inter-observer-variability and some technical problems. In contrast, the monoclonal EIA stool test is highly reliable, both pre- and post therapy, and equivalent to the (13)C-urea breath test.