Comparison of a Stool Antigen Test and Serology for the Diagnosis of Helicobacter pylori Infection in Mass Survey

Background: Serum antibody to Helicobacter pylori is tested in mass screening for gastric cancer along with the level of serum pepsinogens (PG) I and II. Recently, stool antigen tests have been developed as a new non-invasive test. We examined H. pylori infection by both serology and stool antigen test in a mass survey and compared the results to estimate applicability of stool antigen test for mass survey.
Methods: A total of 994 healthy adults who received mass survey in April 2005 were tested. There were 379 men and 615 women, and the mean age was 57.7 years old. Stool samples were used to measure a H. pylori- specific antigen by enzyme immunoassay. Serum samples were tested for the prevalence of IgG antibody to H. pylori , and the level of PGs I and II was also measured to determine the presence of atrophic gastritis.
Results: Infection of H. pylori was defined as positive 61.4% and 56.4% by serology and stool antigen test, respectively. The concordance of both tests was not affected by gender and age of the subjects but difference was seen in subjects with atrophic gastritis. In particular, positivity of stool antigen test (81.8%) was significantly lower than that of serology (88.7%, p  < .05) in 303 subjects with severe atrophic gastritis.
Conclusions: Stool antigen test, which detects present but not previous infection of H. pylori , would be applicable to diagnose H. pylori infection in mass survey. Usefulness of stool antigen tests for the screening of gastric cancer should be examined.     

Helicobacter pylori colonization in the first 3 years of life in Japanese children

BACKGROUND: Acquisition of Helicobacter pylori infection occurs in early childhood, but the exact time of the acquisition and dynamics of infection are not clear. The aim of this study was to estimate the time of acquisition of H. pylori colonization in infants. SUBJECTS AND METHODS: This prospective follow-up study included 237 infants born in Wakayama Rosai Hospital from February, 2001 to April, 2002. Stool samples were collected at indicated ages, and H. pylori antigens were determined by a stool antigen test, HpSA. RESULTS: One-hundred and eight infants among initially enrolled 237 children have been followed up until 24 months. Among these, 16 infants turned to be HpSA positive within 12 months, but only four remained positive by the consecutive tests with optical density values of more than 0.7. They were assumed persistent positives. The rest 12 infants reverted to be negative by the consecutive tests and were assumed transient or false-positives. The optical density values of HpSA in the transient cases were exclusively less than 0.35. CONCLUSIONS: The consecutive follow up of HpSA, but not the one-point test, might be useful to diagnose persistent colonization of H. pylori in young infants, and some infants seemed to acquire H. pylori infection in the first year of life. These results should be taken into account for prevention and treatment strategies for H. pylori infection in infants.     

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.     

Epidemiology and Diagnosis of Helicobacter pylori Infection

Medline, PubMed and the Cochrane databases were searched on epidemiology and diagnosis of Helicobacter pylori for the period of April 2011-March 2012. Several studies have shown that the prevalence of H.?pylori infection is decreasing in adults and children in many countries. Various diagnostic tests are available, and most of them have high sensitivity and specificity. The Maastricht IV/Florence consensus report states that the urea breath test using (13) C urea remains the best test to diagnose H.?pylori infection. Among the stool antigen tests, the ELISA monoclonal antibody test is recommended. All these tests were used, either as a single diagnostic test or in combination, to investigate H.?pylori infection among different populations throughout the world. Of particular interest, current improvements in high-resolution endoscopic technologies enable increased diagnostic accuracy for the detection of H.?pylori infection, but none of these techniques, at present, are specific enough for obtaining a real-time diagnosis of H.?pylori infection.     

Novel monoclonal antibody-based Helicobacter pylori stool antigen test

BACKGROUND: A number of noninvasive tests have been developed to establish the presence of Helicobacter pylori infection. Although polyclonal antibody-based stool antigen testing has a good sensitivity and specificity, it is less accurate than urea breath testing. Recently, a monoclonal antibody-based stool antigen test demonstrated an excellent performance in diagnosing H. pylori infection in adults and in pediatric populations. AIM: To evaluate the diagnostic accuracy of a novel stool test based on monoclonal antibodies to detect H. pylori antigens in frozen human stool in the pretreatment setting. PATIENTS AND METHODS: Stool specimens were prospectively collected from 78 patients undergoing gastroscopy and stored at -20 degrees C until tested. Helicobacter pylori infection was evaluated by histology, rapid urease testing and urea breath tests ((13)C-UBT). Positivity of the three tests was considered the gold standard for H. pylori active infection. Patients with no positive test were considered negative. The gold standard was compare to the results of the monoclonal antibody stool antigen test. Frozen stool specimens were tested using a novel monoclonal-antibody-based enzyme immunoassay (HePy-Stool, Biolife-Italiana, Milan, Italy). RESULTS: The sensitivity and specificity of the monoclonal stool antigen test were 97%[95% confidence interval, (CI) 86-100] and 94% (95% CI: 81-99), respectively. Negative and positive predictive values were 97% (95% CI: 85-99), and 95% (95% CI: 83-99), respectively. The diagnostic accuracy was 96% (95% CI: 88-99). The likelihood ratio for a positive test was 17 and for a negative test was 0. CONCLUSIONS: Although the (13)C-UBT is the most accurate among the available noninvasive tests, our results show that an H. pylori stool test using monoclonal antibody might be an excellent alternative.     

Problem of distinguishing false-positive tests from acute or transient Helicobacter pylori infections

BACKGROUND: Reliable detection of acute Helicobacter pylori infections remains problematic. The high prevalence of false-positive non-invasive tests in low H. pylori prevalence populations makes identification of acute and transient infections difficult. METHODS: We explored the use of serum pepsinogens (PG) for diagnosis of acute infection in patients following H. pylori challenge such that the onset of the infection was known. We then compared those findings to a group of children with presumed acute infections defined as a positive urea breath test (UBT) and negative IgG serology. RESULTS: We examined the pattern and calculated cut-off values of PG levels in 18 adult volunteers with known acute H. pylori infection. We then compared the results with sera from nine symptomatic children with presumed acute H. pylori infection and a matched control group of nine children who did not meet criteria for acute H. pylori infection. In acute infection, both PGI and II levels increased following H. pylori infection reaching a peak by 2 weeks post-infection. The frequency of a positive test defined as a value > mean +2 SD was 17, 71, and 94% at week 1, 2, and 4 post-infection, respectively. Only one child with presumed acute H. pylori infection had an elevated serum PGI and one had an elevated PGII. Five of the children had follow-up UBTs and four were negative consistent with the diagnosis of false-positive UBT. H. pylori infection was confirmed in the child with an elevated PGI level. CONCLUSIONS: These data suggest that a single positive noninvasive test in populations of low prevalence is most likely a false-positive result. This suggests that a single positive test requires confirmation preferably using a test that measures a different parameter (e.g., UBT confirmed by stool antigen test). It appears that most "transient"H. pylori infections are diagnosed on the basis of false-positive tests. PG levels are possible candidates as the confirmatory test.     

Diagnosis of Helicobacter pylori Infection

The articles published this last year in the field of Helicobacter pylori diagnosis reported the development of in vivo histology, small improvements in some invasive methods (urease test, culture, and histology) and new kits for the stool antigen tests. They also contributed to increasing our knowledge, by further exploration into specific conditions for the urea breath test and into the significance of cag A antibodies. The role of serum markers of atrophy was also confirmed. Molecular methods are still being developed for direct genotyping, detection of H. pylori and its clarithromycin resistance, either by polymerase chain reaction or fluorescent in-situ hybridization. For the first time, there was a report on a possible interest of magnetic resonance spectroscopy.     

Helicobacter pylori stool antigen test in patients with bleeding peptic ulcers

BACKGROUND: Helicobacter pylori has been linked to chronic gastritis, peptic ulcers, gastric cancer and mucosa-associated lymphoid tissue lymphoma. Invasive tests are less sensitive than noninvasive tests in diagnosing H. pylori infection in patients with bleeding peptic ulcers. The H. pylori stool antigen test has been useful in diagnosing H. pylori in patients with peptic ulcers before and after eradication of H. pylori. The aim of this study was to evaluate the H. pylori stool antigen test in patients with bleeding peptic ulcers. METHODS: Patients with bleeding and nonbleeding peptic ulcers underwent a rapid urease test, histology, bacterial culture and H. pylori stool antigen test. Positive H. pylori infection was defined as a positive culture or both a positive histology and a positive rapid urease test. Helicobacter pylori stool antigen was assessed with a commercial kit (Diagnostec H. pylori antigen EIA Kit, Hong Kong). RESULTS: Between October 2000 and April 2002, 93 patients with bleeding peptic ulcers (men/women: 78/15, gastric ulcer/duodenal ulcer: 58/35) and 59 patients with nonbleeding peptic ulcers (men/women: 47/12, gastric ulcer/duodenal ulcer: 30/29) were enrolled in this study. Forty-seven (50.5%) patients with bleeding peptic ulcers and 30 (50.8%) patients with nonbleeding peptic ulcers, were found to be infected with H. pylori (p > .1). Helicobacter pylori stool antigen tests were positive in 54 (58.1%) and 30 (50.8%) patients with bleeding peptic ulcers and nonbleeding peptic ulcers, respectively (p > .1). The sensitivity (82% vs. 93%), specificity (68% vs. 93%), positive predictive value (74% vs. 93%), negative predictive value (77% vs. 93%) and diagnostic accuracy (75% vs. 93%) were all lower in patients with bleeding vs. nonbleeding peptic ulcers. The specificity, positive predictive value, and diagnostic accuracy of the H. pylori stool antigen test in patients with bleeding peptic ulcers were significantly lower than those in patients with nonbleeding peptic ulcers (p = .01, p = .02 and p = .003, respectively). CONCLUSION: The H. pylori stool antigen test is not reliable for diagnosing H. pylori infection in patients with bleeding peptic ulcers.     

Helicobacter pylori Infection in Pediatrics

This review summarizes the articles published on Helicobacter pylori infection in children between April 2008 and March 2009. Recent evidence highlights the decreasing prevalence trend of H. pylori infection and supports both intrafamilial and extrafamilial transmission. The association with various symptoms is still being debated. Interestingly, H. pylori infection seems inversely associated with allergic diseases. Monoclonal stool antigen tests are widely used and accurate for the diagnosis of H. pylori infection, but less accurate in young children. The new biprobe real-time PCR assay applied to stools showed a poor sensitivity in children. Using the urea hydrolysis rate next to the delta over baseline values, the ¹³C-urea breath test provides excellent results for all age children, even for young children. Treatment of H. pylori infection remains a challenge, considering suboptimal efficacy of current therapy. Among emerging alternatives, sequential treatment appears promising. The adjunction of probiotics to conventional regimens, although eliciting great interest, has shown limited therapeutic benefit.     

Evaluation of stool antigen test, PCR on ORAL samples and serology for the noninvasive detection of Helicobacter pylori infection in children

BACKGROUND: Endoscopy represents the gold standard for the diagnosis of Helicobacter pylori infection. We evaluated three noninvasive tests in a group of children: the immunoassay for detection of H. pylori stool antigen, the polimerase chain reaction for identification of bacterial DNA on the oral cavity and the serum specific antibodies. MATERIALS AND METHODS: One hundred and ninety children underwent endoscopy for various gastrointestinal symptoms. H. pylori stool antigen and anti-H. pylori antibodies were assayed by commercial kits. The bacterial DNA on saliva and oral plaque was detected by a seminested PCR. RESULTS: Based on the positivity of culture or urease rapid test and histology, infection was detected in 47 patients. The statistical analysis showed that, for the detection of the infection, stool antigen assay is more effective in sensitivity and negative predictive value (91.5% and 96.5%), whereas specificity and positive predictive values appear slightly better in serology (89.6% and 76.0%). Correlations between serum IgG both with patients' age (r = 0.21, p < .05) and H. pylori stool antigen (r = 0.47, p < .01) were found. The search for bacterial DNA on oral samples proved to be very specific (99.1% on saliva and 98.2% on plaque), but insensitive (22.2% and 25.7%). CONCLUSIONS. In children H. pylori stool antigen represents a sensitive test, suitable for detecting H. pylori infection. Serum IgG proved to be more specific; the PCR on the oral cavity resulted as being a very specific, but insensitive test.     

Comparison of five detection methods for Helicobacter pylori

OBJECTIVE: To evaluate which diagnostic test is preferable for the diagnosis of Helicobacter pylori in patients with gastroduodenal disease. STUDY DESIGN: H pylori infection was diagnosed prospectively in 101 patients. Diagnosis of H pylori was made by tests based on five different principles: (1) culture, (2) direct histologic demonstration, (3) imprint cytology, (4) brushing cytology, and (5) gram staining of H pylori. Efficacy of each test was compared. RESULTS: All the tests were reliable for diagnosing H pylori infection; 73.3% of patients showed concordance in at least two tests. All the tests were positive in > 50% of patients. Significant concordance between brushing and imprint cytology was also determined. These two tests have almost similar specificity when compared to other tests. CONCLUSION: When patients undergo upper endoscopy, we recommend taking biopsy specimens for culture and histology. H pylori can be assessed equally well with all the tests, but imprint and brushing cytology have the advantage of rapid response, specificity, much lower cost and reproducibility.     

Methodology and transport medium for collection of Helicobacter pylori on a string test in remote locations

BACKGROUND: Helicobacter pylori can be isolated from patients using the string test but contaminating oral and nasopharyngeal microflora need to be suppressed by rapid plating out onto selective culture media. Recently, use of this diagnostic method was enhanced by using a novel transport medium to collect specimens from subjects in a remote Australian clinic over 1300 km from the laboratory. METHODS: Retrieved string tests were transported to the laboratory in chilled polystyrene boxes in 5 ml screw-cap bottles with 3 ml of a brain heart infusion broth plus antibiotics. These were 20 g/ml vancomycin, 10 g/ml trimethoprim, 10 g/ml cefsulodin, and 10 g/ml amphotericin B. A comparison was made between subjects who gargled with a chlorhexidine mouthwash before swallowing the string test and those who did not. RESULTS: Forty-five urea breath test-positive subjects were tested and H. pylori was isolated from 34 of them. Successful culture was achieved from string tests that were in transit for up to 29 hours and where the maximum temperature in the transport box was 14 degrees C. The additional use of a mouthwash had a marked effect on the isolation rate. H. pylori was cultured from 75% of subjects who gargled but only from 39% who did not. CONCLUSIONS: This methodology and transport medium can broaden the use of the string test to more remote geographic areas where endoscopy is not feasible so that H. pylori isolates may still be obtained for diagnostic and epidemiologic studies. The value of this promising methodology of collection and transport should be assessed in a controlled study.     

Role of noninvasive tests (C-urea breath test and stool antigen test) as additional tools in diagnosis of Helicobacter pylori infection in patients with atrophic body gastritis

BACKGROUND: Detection of Helicobacter pylori infection in atrophic body gastritis (ABG) is difficult, as during progression of body atrophy, H. pylori disappears. AIM: To increase the diagnostic yield of detection of active H. pylori infection in atrophic body gastritis patients by using noninvasive tests such as (13)C-Urea Breath Test ((13)C-UBT) and H. pylori stool antigen test (HpSA) would be useful. PATIENTS: 27 consecutive patients with newly-diagnosed atrophic body gastritis (19F/7M, age 27-73 years). METHODS: Gastroscopy with biopsies (antrum n = 3, body n = 3) and histology according to updated Sydney system, H. pylori IgG serology, (13)C-UBT, and HpSA. RESULTS: All tests used in the diagnosis of H. pylori infection were in agreement in 9/27 atrophic body gastritis patients (33.3%), being all positive in four (14.8%) and all negative in five patients (18.5%). Ten of the 27 (37%) patients were Giemsa stain-positive and serology-positive (group I). Seventeen of the 27 (63%) patients were Giemsa stain-negative: 5/17 with positive serology (group II) and 12/17 with negative serology (group III). In group I, 5/10 (50%) were (13)C-UBT positive and 4/10 (40%) HpSA positive. In group II, two patients were (13)C-UBT positive, but all were HpSA negative. Also in group III, all patients were HpSA negative, but one had a positive (13)C-UBT. CONCLUSIONS: In atrophic body gastritis patients, neither (13)C-UBT nor HpSA per se add useful information regarding active H. pylori infection, but these noninvasive tests may be important in combination with histology and serology to define the H. pylori status in some atrophic body gastritis patients.     

体外~(14)C-尿素呼气试验检测胃内幽门螺杆菌感染研究

目的　建立诊断胃内幽门螺杆菌感染 (Hp)的体外 1 4 C-尿素呼气试验 (1 4 C- U BT)。方法　 47例 Hp阳性和 32例 Hp阴性患者接受测试 ,用口服微量胃液采集胶囊的办法收集胃液标本于一 10 m l无菌试管内 ,加入生理盐水 0 .5 m l和 18.5 k Bq1 4 C-尿素后立即加橡皮塞密封试管 ,室温放置反应 3h,注射器经橡皮塞注入 2 M H2 SO41.0 ml,使 1 4 CO2 释出。同一注射器回抽气体并立即注入装有 6 .5 ml的 1 4 CO2 搜集闪烁剂液闪瓶内搜集 1 4 CO2 ,最后在液体闪烁计数仪上作 1 4 C放射性测定。结果　 47例 Hp阳性病人 1 4 C放射性几何均数为 5 30 dpm,而 32例 Hp阴性者结果为 2 1dpm,二者相差 2 3倍 (Wilcoxon秩和检验 ,u=5 .5 976 ,P<0 .0 1)。以受试者工作特征曲线分析法得出判别阈值为 75 dpm ,对 Hp诊断的敏感性和特异性为 92 %(4 3/ 47)和 91% (2 9/ 32 )。结论　体外 1 4 C- UBT诊断 Hp感染具有高度的准确性 ,无放射性损伤之虞 ,可适用于临床诊断。     

Detection of specific Helicobacter pylori DNA and antigens in stool samples in dyspeptic patients and healthy subjects

In this study stool samples from dyspeptic patients and healthy subjects were used for detection of specific Helicobacter pylori antigens and DNA by immunoenzymatic test (PPHpSA) and semi-nested PCR (ureA-PCR), respectively. The H. pylori status was estimated by invasive endoscopy-based rapid urease test and histology or noninvasive urea breath test (UBT), and by serology (ELISA, Western blot). The coincidence of H. pylori-negative invasive tests or UBT and negative antigen or DNA stool tests was very high (mean 95%). The PPHpSA results were found positive for 56% and ureA-PCR for 26% of individuals with H. pylori infection confirmed by invasive tests or UBT. The detection of specific H. pylori antigens and especially DNA in feces is not sufficient as a one-step diagnosis of H. pylori infection.     

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.     

Applications of the Poly-K Statistical Test to Life-Time Cancer Bioassay Studies

The statistical analysis of cancer bioassay data has historically depended on the pathological determination of the experimental animal's cause of death. The poly-k statistical test has provided a method of statistical analysis of animal bioassay data without the need for cause of death information. The test has been shown to have good statistical properties in the typical 2-year cancer bioassay. However, while the poly-k test has been applied to chronic lifetime animal studies, it has not been formally evaluated with respect to the operating characteristics of this statistical test when applied to such studies. Thus, our objective is to assess the performance of the poly-k test for lifetime studies and to make comparisons with other tests. We observed in one recent lifetime study of the gasoline additive methyl tertiary butyl ether (MTBE) that the application of the poly-k test was not statistically robust. Simulation studies were subsequently conducted for a limited number of scenarios of lifetime cancer bioassays. These simulations showed that the poly-k test is not statistically robust for testing effect of increasing dose in some lifetime cancer studies.     

Multicenter comparison of rapid lateral flow stool antigen immunoassay and stool antigen enzyme immunoassay for the diagnosis of Helicobacter pylori infection in children

BACKGROUND AND AIM: The stool antigen enzyme immunoassay (EIA) methods are widely used for diagnosing Helicobacter pylori infection. Recently, a novel, rapid stool antigen test, the lateral flow immunoassay (LFI) method, has been developed. The primary purpose of this study was to compare the EIA method with the LFI method for the diagnosis of H. pylori infection in children. MATERIALS AND METHODS: Stool specimens from children being evaluated for H. pylori infection were also examined using the LFI (ImmunoCard STAT! HpSA) and EIA methods (Premier Platinum HpSA). The sensitivity, specificity and accuracy of the test were based on the 13C-labeled urea breath test. RESULTS: One hundred and eighty-two children and adolescents, 3-17 years of age (mean 9.2 years), were studied. In addition, 29 patients who received eradication therapy were re-evaluated 2 or 3 months post-treatment. The 13C-labeled urea breath test was positive in 64 patients (35.2%). The sensitivity, specificity and accuracy of the LFI method were 90.6% (95% CI = 80.7-96.5%), 95.8% (92.1-99.4%), and 94.0% (90.5-97.4%), respectively and for the EIA method, sensitivity, specificity and accuracy were 96.8% (95% CI, 89.0-99.6%) and 99.2% (97.5-100%), and 98.3% (96.5-100%), respectively. There were no significant differences in results among the age groups 3-5, 6-10 and 11-17 years. As for the assessment of H. pylori eradication, the results of the LFI and EIA methods agreed with those of 13C-urea breath test in 27/29 and 29/29 patients, respectively. CONCLUSIONS: The LFI stool antigen method showed a good sensitivity, specificity and accuracy for diagnosing H. pylori infection in children. This novel method may be useful in clinical practice as an office-based test because it is rapid, reliable and easy to perform.     

Proof of an association between Helicobacter pylori and idiopathic thrombocytopenic purpura in Latin America

BACKGROUND: Association between Helicobacter pylori and idiopathic thrombocytopenic purpura (ITP) has been found in Japan and in some European countries. It has also been shown that eradication of H. pylori can increase platelet counts in patients with ITP. The aims of this study were to determine the prevalence of H. pylori infection in patients with ITP in Colombia, and the effect of bacterial eradication on their platelet counts. MATERIALS AND METHODS: Between December 1998 and April 2006, a total of 32 patients diagnosed with ITP were included in the study. Controls were age and sex matched. RESULTS: H. pylori infection in patients with ITP was significantly higher (p = .00006) than in control individuals (90.6% and 43.8%, respectively), as determined by (13)C-urea breath test. A significant association between H. pylori infection and ITP was found (p < .0003), with an odds ratio (OR) of 13.15 (95%CI: 3.24-53.29). Multivariate analysis for the association between H. pylori and ITP showed an OR of 20.44 (95%CI: 3.88-107.49) for women and 19.28 (95%CI: 2.03-183.42) for individuals over 50 years. All 29 H. pylori-positive patients with ITP received eradication treatment. After a median follow up of 12.2 months, 80.8% had a recovery in platelet counts. CONCLUSIONS: According to these results and others from different countries where H. pylori infection rates are high, patients with ITP should be initially tested for H. pylori status, and if present, infection should be eradicated before initiating a drastic conventional ITP treatment. An algorithm for the study and management of patients with ITP in the post-Helicobacter era is presented.