Helicobacter pylori stool antigen (HpSA) test--a simple, accurate and non-invasive test for detection of Helicobacter pylori infection

BACKGROUND/AIMS: To access the reliability of a newly developed test, the Helicobacter pylori (H. pylori) stool antigen (HpSA) test was used for detection of H. pylori infection. METHODOLOGY: Stool specimens were collected from 33 consecutive patients (19 males and 14 females, age range: 16-73 years, mean: 49 years) who received upper gastrointestinal endoscopic examination for gastrointestinal symptoms. The H. pylori status was evaluated based on six different tests: culture, histology, biopsy urease test, 13C-urea breath test (13C-UBT), serology, and HpSA test. A commercial kit using an enzyme-linked immunosorbent assay examined HpSA in the stool. H. pylori status was defined as positive when the culture was positive or concordance of three of the other four tests (histology, biopsy urease test, 13C-UBT, and serology) was positive. RESULTS: Twenty patients were diagnosed as H. pylori-positive. The HpSA test was positive in 19 patients and negative in 14 patients. The sensitivity and specificity were 95.0% and 100%, respectively. The overall accuracy rate was 96.3%. CONCLUSIONS: The HpSA test is a new, simple, non-invasive method for accurate diagnosis of H. pylori infection.     

Diagnostic accuracy of the 13C-urea breath test for childhood Helicobacter pylori infection: a multicenter Japanese study

OBJECTIVES: In adults, the 13C-urea breath test (UBT) has been widely used as a noninvasive test of Helicobacter pylori infection because of its high sensitivity and specificity. However, this test is less well established in pediatric practice. The optimum cutoff value and test protocol of the 13C-UBT remains to be established in the pediatric population. The primary purpose of this study was to evaluate diagnostic accuracy of the 13C-UBT for children and to determine its optimum cutoff value. METHODS: A total of 220 Japanese children aged 2-16 yr (mean = 11.9) who underwent upper GI endoscopy and gastric biopsies were finally studied. Endoscopic diagnoses included gastritis (n = 131), gastric ulcer (n = 15), duodenal ulcer (n = 72), and combined ulcer (n = 2). H. pylori infection status was confirmed by biopsy tests including histology, urease test, and culture. With the 13C-UBT, breath samples were obtained at baseline and at 20 min after ingestion of 13C-urea without a test meal and were analyzed by isotope ratio mass spectrometry. Based on biopsy tests, a cutoff value was determined using a receiver operating characteristic curve. In 26 children (seven children infected and 19 noninfected), paired breath samples were also measured by nondispersive infrared spectometry (NDIRS). RESULTS: Biopsy tests demonstrated that 89 children (40%) were infected with H. pylori and 131 children were not infected. There were no statistical differences in mean delta 13C values at 20 min between male and female H. pylori-infected and noninfected patients. A receiver operating characteristic analysis defined the best cutoff value as 3.5 per thousand. The overall sensitivity and specificity at a cutoff value of 3.5 per thousand were 97.8% (95% CI = 92.1-99.7%) and 98.5% (95% CI = 96.4-100%), respectively: high sensitivity and specificity were demonstrated in all three age groups (< or =5, 6-10, and > or = 11 yr). There was a close correlation between the values with isotope ratio mass spectrometry and NDIRS methods (r = 0.998, p < 0.001). CONCLUSIONS: The 13C-UBT with a cutoff value of 3.5 per thousand is an accurate diagnostic method for active H. pylori infection. The test with the NDIRS method is inexpensive and might be widely applied in clinical practice.     

Diagnosis of Helicobacter pylori infection in patients with atrophic gastritis: comparison of histology, 13C-urea breath test, and serology

BACKGROUND: Atrophic gastritis, a risk factor for gastric cancer, is a late consequence of Helicobacter pylori infection in approximately one-third of the infected patients. It has been suggested that gastric cancer would develop less frequently if H. pylori were eradicated. However, the prevalence of H. pylori infection may be underestimated in patients with atrophic gastritis and intestinal metaplasia if only biopsy-based diagnostic methods are used. METHODS: We compared histology, 13C-urea breath test (13C-UBT), and serology in H. pylori diagnostics in 50 male patients with atrophic corpus gastritis. RESULTS: H. pylori was detected in 15 (30%) patients by histology and in 14 (28%) by 13C-UBT, whereas increased serum antibody levels indicating H. pylori infection were found in 41 (82%) patients (P < 0.0001 between serology and both histology and 13C-UBT). H. pylori infection was associated with atrophic corpus gastritis in 84% of the present patients (in one patient with normal antibody titres H. pylori was defined histologically). CONCLUSIONS: H. pylori infection would have been missed in most patients with atrophic gastritis without the analysis of H. pylori antibodies. Therefore, in patients with atrophic gastritis, the use of serology is encouraged in diagnosing H. pylori infection.     

The clinical utility of string-PCR test in diagnosing Helicobacter pylori infection

BACKGROUND/AIMS: Non-invasive string test has been reported as being convenient and capable of yielding bacteria by means of gastric juice sampling in the diagnosis of Helicobacter pylori infection. Molecular methods, such as polymerase chain reaction for the amplification of DNA, are desirable for the detection of minute quantities of H. pylori. We planned to evaluate the diagnostic efficiency of the combination of the string test and polymerase chain reaction and determine whether the string polymerase chain reaction test could obtain more information in conditions where the bacterial load is so low that other diagnostic tests fail to confirm the presence of H. pylori. METHODOLOGY: We enrolled 48 dyspeptic patients, including 29 males and 19 females, with a mean age of 52.5 years. Each patient received endoscopy and biopsy-based tests, including RUT (rapid urease test), cultures, and histology, followed by 13C-UBT (13Carbon urea breath test). We used the string test, (Entero-Test H. pylori, HDC Corporation, CA, US), for gastric juice sampling. The specimen was further analyzed by polymerase chain reaction for the presence of H. pylori with the primer for cagA gene, which is highly prevalent in Taiwan. H. pylori infection was considered as positive when either culture yield was positive, or when two of the other three tests, including RUT, histology, and 13C-UBT, were positive. RESULTS: Of the total 48 patients, 34 patients were H. pylori-positive, and 14 were H. pylori-negative. A fragment of 349 bp of polymerase chain reaction products was detected by agarose gel electrophoresis in 32 out of 34 patients who was classified as H. pylori-positive. The sensitivity, specificity, positive predictive value, and negative predictive value of the string polymerase chain reaction test were 94.12%, 96.97%, 92.86%, and 86.67%, respectively. These results are comparable to 13C-UBT and RUT, and better than histology and culture. One subject, who tested as H. pylori-negative according to the diagnostic criteria, had positive 13C-UBT and string polymerase chain reaction test results. Further sequencing of the DNA obtained from the results of polymerase chain reaction product was performed and it showed 98% identities with the known sequence of cagA strain H. pylori (GenBank accession number: AF249275). CONCLUSIONS: The string polymerase chain reaction test is non-invasive and provides direct bacterial yields. Its diagnostic efficiency is comparable with 13C-UBT and RUT in detecting H. pylori infection. Also, with the assistance of polymerase chain reaction and DNA sequencing, we can diagnose H. pylori infection even when the bacterial load is low. Further application of string polymerase chain reaction test in the genetic analysis of virulent and resistant strains seems promising.     

Diagnosis of Helicobacter pylori infection by stool antigen test in southern Taiwan

Helicobacter pylori (H. pylori) has been found to be associated with various gastrointestinal diseases. Confirmation of H. pylori infection includes invasive and non-invasive methods. There has been increasing interest in noninvasive tests recently. However, the geographical differences among H. pylori strains have been emphasized recently and the H. pylori strain in Taiwan showed a high cagA positive result and different vacA subtype when compared with those of Western countries. The aim of this study is to access and compare the reliability and the diagnostic accuracy of the stool H. pylori antigen tests by spectrophotometry and by the visual method, especially in Southern Taiwan. Thirty-two patients (18 men and 14 women; age range: 23-91 y/o, mean: 50.5 y/o) who underwent gastroendoscopy at Kaohsiung Medical University Hospital were enrolled in this study. H. pylori infection status was confirmed by culture or two positive test results on CLO test, histology and 13C-urea breath test (13C-UBT). The exclusion criteria included previous gastrointestinal tract surgery, use of antibiotics, proton pump inhibitor or compounds containing bismuth within 1 month of the study. Among them, 14 patients were with duodenal ulcer (DU), 4 with gastric ulcer (GU), 12 with non-ulcer dyspepsia, and 2 with GU and DU. Those patients had their stool collected for ELISA tests of H. pylori stool antigen (HpSA). The HpSA tests were positive in 16 of 18 patients diagnosed as H. pylori positive, and negative in 13 of 14 patients as H. pylori negative. The sensitivity and specificity were 88.9% and 92.9% respectively. The positive and negative predictive values were 94.1% and 86.7% respectively. The concordance of HpSA accessed by spectrophotometry and visual method is 100%, which makes this test even easier and cheaper. We concluded that stool HpSA test is a noninvasive, accurate, reliable, rapid and easy way to diagnose H. pylori infection in Southern Taiwan, either by spectrophotometry or by visual assessment.     

Diagnostic accuracy of (13)C-urea breath test in the diagnosis of Helicobacter pylori infection in patients with partial gastric resection due to peptic ulcer disease: a prospective multicenter study

AIMS: We investigated the diagnostic properties of the (13)C-urea breath test ((13)C-UBT) prospectively. These are well validated in nonresected patients before and after treatment of Helicobacter pylori infection but not in patients with partial gastric resection due to peptic ulcer disease. METHODS: Hospitalized patients with previous gastric resection and indications for upper gastrointestinal endoscopy were recruited for the study. Biopsy specimens were obtained from the fundus mucosa and the gastric remnant adjacent to the gastroenteric anastomosis for histological examination and rapid urease test (HUT test). Histological slides were evaluated after hematoxylin and eosin and Warthin-Starry dye staining. 200 ml orange juice was given orally after two baseline breath samples had been taken, and 30 min after ingestion of 75 mg (13)C urea two more breath samples were obtained and analyzed by ratio mass spectrometry. The Warthin-Starry dye-stained sample was taken as reference. RESULTS: 68 patients (47 male, 21 female, mean age 62 years; 52 Billroth II resection, 17 Billroth I resection) were included in the study. The overall prevalence of histologically proven H. pylori infection was 36.7%. The sensitivity of the (13)C-UBT was 52%, the specificity 93%. The positive predictive value was 81.25%, the negative predictive value 76.9% and the accuracy was 77.9%. The sensitivity of the HUT test reached 60%, and the specificity 97%. CONCLUSION: The diagnostic accuracy of (13)C-UBT compared with the Warthin-Starry dye staining is low. The breath test, performed in the above-described manner, cannot be recommended as a noninvasive diagnostic tool for diagnosis of H. pylori infection in patients after partial gastrectomy as a result of peptic ulcer disease.     

Noninvasive tests as a substitute for histology in the diagnosis of Helicobacter pylori infection

BACKGROUND: Rapid urease tests for Helicobacter pylori have a sensitivity of 80% to 90%. Therefore histologic examination of gastric biopsies is recommended as a "backup" diagnostic test in rapid urease test-negative patients. However, noninvasive tests (urea breath test, serology, whole blood antibody tests) may provide a more rapid diagnosis and be less expensive but offer similar accuracy. METHODS: Sixty-seven patients (no prior treatment for H pylori, no proton pump inhibitors, antibiotics, or bismuth within 4 weeks) undergoing endoscopy for evaluation of dyspepsia symptoms and testing rapid urease test-negative by antral biopsy were enrolled. All had the following tests: gastric biopsies (2 antral, 1 fundus; H&E and Alcian Yellow stain) examined for gastritis and H pylori; (13)C-UBT; capillary blood for whole blood rapid antibody tests: FlexSure HP, QuickVue, AccuStat, and Stat-Simple Pylori; serum for FlexSure HP; HM-CAP enzyme-linked immunoassay. H pylori infection was diagnosed (reference standard) if chronic gastritis was present on histology and at least 2 of the 3 following tests were positive: urea breath test, H pylori organisms unequivocally demonstrated in biopsies on special stain, and/or enzyme-linked immunoassay. The test and treatment costs per patient were calculated. RESULTS: Of 67 patients with a negative rapid urease test, 4 were positive for H pylori. None had active peptic ulcer disease. Histology only identified 1 patient with organisms visible on special stain. Using chronic active gastritis (neutrophilic and mononuclear infiltrate) as a diagnostic criterion for H pylori, 6 patients would have been judged positive. However, only 2 of these were truly positive by the reference standard (positive predictive value 33%). Negative predictive value for presence of organisms and chronic active gastritis was 95% and 97%, respectively. All of the noninvasive tests identified all 4 truly positive patients correctly. Urea breath test and FlexSure whole blood assay yielded a substantial number of false-positive results (positive predictive value 31% and 36%, respectively); positive predictive value for the other tests ranged from 50% to 80%. All tests except histology had a negative predictive value of 100%. Histology was the most costly test (p < 0. 001 compared with all other tests), followed by urea breath test and HM-CAP serology (p < 0.001 compared with all rapid antibody tests). CONCLUSIONS: Whole blood or serum antibody testing is a rapid, accurate, and cost-effective means for establishing H pylori status in rapid urease test-negative patients. Whole blood or serology rapid antibody testing should substitute for histology when the patient has not been previously treated for H pylori.     

Diagnosis of Helicobacter pylori infection in patients with bleeding ulcer disease: rapid urease test and histology.

INTRODUCTION: The endoscopic diagnosis of Helicobacter pylori infection in patients with bleeding peptic ulcer is limited by a decreased sensitivity in standard invasive tests, rapid urease test and histology. There is controversy about the convenience of using one, neither, or both diagnostic tests. AIMS: To evaluate the results of simultaneously performed rapid urease test and histology in the diagnosis of Helicobacter pylori infection (H. pylori) in patients with bleeding peptic ulcer. PATIENTS AND METHODS: We included 173 patients, 98 male and 75 female, with an average age of 62 years (18-88), with upper gastrointestinal bleeding secondary to duodenal ulcer (115) or gastric ulcer (58), diagnosed within 24 hours after hospital admission. None of the patients had received treatment for H. pylori, proton pump inhibitors or antibiotics in the two weeks prior to the upper gastrointestinal bleeding episode. H. pylori infection was investigated in all patients by two antral biopsy samples for histological study (hematoxilin-eosin) and one or two antral biopsies for rapid urease test (Jatrox-H.p.-test). In cases with a negative urease test and histology, a 13C urea breath test was performed. Infection was considered present when at least one invasive test or the breath test was positive, whereas both invasive tests and the breath test had to be negative to establish an absent infection. RESULTS: 152 patients (88%) showed H. pylori infection, 104 patients (90%) with duodenal ulcer and 48 patients (83%) with gastric ulcer. In all 119 cases (78%) were diagnosed by the urease test and 112 cases (74%) by histology. Both methods were used to diagnose 134 of 152 cases (88%) (p < 0.05), these being positive in 97 cases and negative in 39 cases. In 18 of these 39 cases, the breath test was positive. CONCLUSIONS: Histology and urease test have similar diagnostic values for the identification of H. pylori in patients with bleeding peptic ulcer. Due to its rapid results, the urease test should be the method of choice. However, additional biopsies should be performed, and, when negative, a histological study should be carried out, since a combination of both methods allows a more precise diagnosis.     

How to determine the diagnosis of Helicobacter pylori infection in the elderly?

PURPOSE: The real prevalence of Helicobacter pylori (H. pylori) infection is difficult to determine in the elderly because of the frequency of drug intake (antibiotics or anti-secretory drugs). The aim of this study was to evaluate the diagnostic performance of five tests in the elderly. METHODS: The study population consisted of consecutive patients undergoing a routine endoscopy between August 1998 and December 1999. We evaluated the diagnostic performance of four tests in all of the included patients: culture and histology of biopsy specimens, serology (ELISA) and urea breath test (13C-UBT). Detection of H. pylori antigens in stool samples (HpSA) was realized in a subgroup. Patients were considered H. pylori + when result for culture was positive or when two tests were positive. RESULTS: One hundred and sixty-seven patients were included in this study (55 men, 112 women; mean age: 85.6 +/- 5.1 years). Only 38 (22.8%) patients were H. pylori+. Test performances showed the following results: serology sensitivity: 90.9% (IC 95%: 75.6-98.1) versus 86.9% (IC 95%: 63.6-96.9) for culture versus 77.8% (IC 95%: 60.8-89.9) for histology and 74.3% (IC 95%: 56.7-87.5) for 13C-UBT. Eighty-nine (53.3%) took antibiotics or anti-secretory drugs, only 13C-UBT performances decreased significantly (sensitivity: 94.4% [72.7-99.8] versus 52.9% [27.8-77]; P < 10(-6)). When gastric or duodenal ulcer were endoscopically diagnosed in older patients, both histology and 13C-UBT could not improve the diagnosis of H. pylori infection. HpSA was realized in 107 patients (sensitivity: 74.1%, specificity: 98.7%). We showed no statistical difference between HpSA performances and drug intake. CONCLUSION: Diagnostic performances decreased in older patients especially because of drug intake.     

老年人幽门螺杆菌粪便抗原检测的价值

目的 评价一种新的酶联免疫法检测老年人粪便中幽门螺杆菌（helicobacter pylori,Hp）特异抗原的可靠性和临床应用价值。方法 因上消化道症状行胃镜检查的老年患者共199例，其中既往无胃手术史者151例，胃大部切除术后者48例。均行胃粘膜活检，作快速尿素酶试验（RUT）和组织学检查（W－S染色），以RUT和W－S染色为金标准，两项均阳性（或阴性）诊断为Hp阳性（或阴性）。所有患者均检查幽门螺杆菌粪便抗原（HpSA）和^13C－尿素呼气试验（^13C-UBT），分别与金标准比较，计算其敏感性和特异性。结果 经金标准诊断，无胃手术史患者中Hp阳性81例，阴性70例。HpSA检测的敏感性和特异性分别为96.3%和90.0%，^13C-UBT为92.6%和92.9%，两种方法的敏感性和特异性差异无显著性。胃大部切除术后患者中Hp阳性23例，阴性25例，HpSA检测的敏感性和特异性分别为91.3%和88.0%，^13C-UBT为65.2%和92.0%，两种方法敏感性差异有显著性（P＜0.05）。结论 HpSA在诊断老年人Hp感染方面准确、快速、简便，值得推广。对于胃大部切除术后的老年患者，其诊断Hp的敏感性明显优于^13C-UBT。     

Detecting Helicobacter pylori infection in hospitalized frail older patients: the challenge

OBJECTIVES: Helicobacter pylori infection has not been well studied in older people, especially in hospitalized, frail patients. The aim of our study was to evaluate the prevalence of the infection in this population using five H. pylori diagnostic tests. DESIGN: Prospective observational study. SETTING: Geriatric acute care unit of the Department of Geriatrics (H?pital Xavier Arnozan, Pessac, France). PARTICIPANTS: One hundred seven consecutively hospitalized patients with a diagnostic indication for upper gastrointestinal endoscopy. MEASUREMENTS: Geriatric assessment, information on drug intake, indication/results of gastric endoscopy, and results of H. pylori infection diagnostic tests (culture and histological analysis on biopsy specimens, serology, 13carbon-urea breath test (13C-UBT), detection of H. pylori stool antigens (HpSA)) were assessed for each included patient. RESULTS: Fifty-one patients (47.7%) were H. pylori positive with at least one test. 13C-UBT was more frequently positive than the other four tests, with a significant difference from culture, histological analysis, and HpSA (P <.05). Positive 13C-UBT results were significantly associated with H. pylori presence using histological analysis and neutrophil activity of the antrum and corpus. Antibiotic treatments significantly decreased the positivity rate of all of the tests performed, and severe corpus atrophy decreased the positivity rate of culture, histological analysis, and HpSA. CONCLUSIONS: Almost one-third of the H. pylori-positive patients would have remained undetected without performing the 13C-UBT. The low prevalence of H. pylori detection in these hospitalized, frail patients may be explained by the high frequency of current and previous antibiotic treatments.     

Accuracy of 13C-urea breath test in clinical use for diagnosis of Helicobacter pylori infection

The 13C-urea breath test (UBT) is a noninvasive test for diagnosis of Helicobacter pylori infection of gastric mucosa. The aim of this prospective study was to assess the accuracy of a simple UBT in clinical routine use. METHODS: The study population comprised of 100 patients (49 f, 51 m) requiring diagnostic upper GI endoscopy. One biopsy specimen was taken from the gastric antrum, body and fundus, respectively, for standard histological examination and one additional specimen from each location was transformed into transport medium for cultivation of H. pylori. After vaccination of the culture plates the biopsies were tested for urease activity (UAT). After recovery from endoscopy the patients had to pass an one liter endexspiratory breath sample before and 15 min after drinking 200 ml orange juice, pH 3.6, containing 75 mg of 13C-urea. 13CO2 was measured in the breath samples using isotope-selective nondispersive infrared spectrometry. RESULTS: Defining gold standard groups with all biopsy tests (from antrum and corpus) positive or negative the 13CO2 delta over baseline (DOB) cut-off level of UBT was set at 6.5/1000 in order to best discriminate positive from negative patients (ROC analysis). UBT was positive in 37% of all subjects. Taken UAT and histological examination together (positive when both tests were positive) UBT displayed a sensitivity of 92%, a specificity of 94%, a positive predictive value of 89%, and a negative predictive value of 94%. When including the results of culture sensitivity and negative predictive value reached almost 100%. The mean of the 13CO2-DOB values from H. pylori-positive duodenal or gastric ulcer patients did not differ from controls (H. pylori-positive patients without lesions). The 13CO2-DOB values of the ulcer group were correlated significantly with the active inflammatory component of gastritis in antrum, corpus, and fundus. CONCLUSION: UBT with this setup detects H. pylori infection in clinical routine use with high accuracy. The increase of exhaled 13CO2 does not predict ulcer disease but reflects the degree of active inflammation of gastric mucosa.     

粪便抗原检测诊断幽门螺杆菌现症感染

目的 评价应用免疫酶联吸附试验(ELISA)检测粪便中幽门螺杆菌(Helicobacter pylori)抗原诊断H.pylori现症感染的敏感性和特异性。方法 应用^14C呼气试验以及幽门螺杆菌粪便抗原(HpSA)试验，对100例因上消化道不适就诊，怀疑有H.pylori感染的患者进行检测，观察两种检查的符合率。结果 ^14C呼气试验和HpSA同时阳性者38例，^14C呼气试验阳性而HpSA阴性者4例；^14C呼气试验和HpSA同时阴性者57例，^14C呼气试验阴性而HpSA阳性1例。以^14C呼气试验作为金标准计算，HpSA检测方法的敏感性为90．48％，特异性为98．28％。结论 幽门螺杆菌抗粪便原检测与^14C呼气试验有较高的符合率，而且简便易行，不需特殊设备，解决了无法进行呼气试验的婴幼儿和有肺部疾患者的非侵人性幽门螺杆菌现症感染诊断问题，是一种非侵入性幽门螺杆菌现症感染诊断的新方法。     

13C-尿素呼气试验在蒙古沙鼠幽门螺杆菌感染检测中的应用

目的　应用13 C -尿素呼气试验检测蒙古沙鼠幽门螺杆菌感染 ,从而建立一长期监控小型试验动物幽门螺杆菌感染无创检测技术。方法　分别在蒙古沙鼠感染幽门螺杆菌后第 2 0 ,5 0 ,10 0及 2 0 0d用13 C -尿素呼气试验进行检测 ,并对检测后沙鼠以细菌分离培养、ELISA、PCR、快速尿素酶试验、病理切片等五种常规方法检测幽门螺杆菌。结果　在上述不同检测时期 ,用13 C -尿素呼气试验所得蒙古沙鼠幽门螺杆菌感染阳性率分别为 77 78% ,83 33% ,84 2 1%和 80 0 0 % ,而应用常规方法检测结果阳性率为 83 33% ,88 88% ,94 2 1%和 85 0 0 %。比较两组试验结果发现 ,13 C -尿素呼气试验比常规检测方法检出阳性率相对偏低 ,但统计学分析发现其具有一致性。结论　13 C -尿素呼气试验用于幽门螺杆菌感染蒙古沙鼠模型检测是一种可行的无创检测方法 ,可作为评价Hp感染的重要参考指标之一     

Use of LARA-urea breath test in the diagnosis of Helicobacter pylori infection in children and adolescents: a preliminary study.

BACKGROUND: An accurate diagnosis of Helicobacter pylori infection in children currently relies upon histological assessment or culture of gastric biopsies obtained at endoscopy. Noninvasive testing would permit simpler assessment of children with dyspeptic symptoms. The primary aim of the present study was to prospectively evaluate a novel urea breath testing method in children undergoing diagnostic assessment of dyspeptic symptoms and secondarily to consider the roles of other noninvasive tests in these children. METHODS: Laser associated ratio analysis (LARA)-13C urea breath testing was performed on children presenting with upper gastrointestinal symptoms for diagnostic endoscopy. Serum and stool were collected for performance of serology and stool antigen testing, respectively. Histology and culture of endoscopic biopsies of the gastric antrum were used to establish H pylori infection status. RESULTS: Eight (36%) of 22 children were H pylori-positive by histology or culture of gastric biopsies. Urea breath testing showed a sensitivity of 75%, but specificity of 100%. The deletion of a test meal from the urea breath test protocol in eight patients did not alter the utility of the test. Serology provided sensitivity of 87.5%, but a specificity of only 75%. Stool antigen testing in eight available samples provided sensitivity of 50% and specificity of 100%. CONCLUSIONS: The LARA-urea breath testing method provided less sensitivity in this group of children than suggested from previous studies. However, urea breath testing in children is easy to complete and provides rapid noninvasive results. Breath testing protocols require standardization; for instance, the addition of a test meal may not be necessary in older children. Although noninvasive tests for the presence of H pylori in children may provide accurate results and can be considered for use in the initial assessment of dyspeptic children, further work is required to establish the most accurate testing methods.     

The CLO test is unreliable in diagnosing H. pylori infection in post-surgical stomach; is there any role of H. pylori in peptic ulcer recurrence?

AIM: To evaluate the validity of the CLO test in detecting Helicobacter pylori in patients with gastric operation and to investigate the relationship of H. pylori with peptic ulcer recurrence in these patients. METHODS: In this prospective study, 110 consecutive patients, the majority of whom had undergone gastric operation for benign disease (n = 102), were included. Eighty patients (62 males), aged 38-87 years, had had a gastrectomy (10 Billroth I, 70 Billroth II), and 30 patients (27 males), aged 36-73 years, had had a vagotomy (13 vagotomy plus gastroenterostomy, 17 vagotomy plus pyloroplasty). H. pylori was sought on multiple biopsy specimens, using CLO test and histology (modified Giemsa stain). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the CLO test were estimated using histology as 'gold standard'. RESULTS: Overall, 21 gastrectomy patients (26%) were H. pylori-positive by CLO and 25 (31 %) were H. pylori-positive by histology. The estimated sensitivity, specificity, PPV and NPV of the CLO test, using histology as 'gold standard', were 68%, 91%, 77% and 86%, respectively. The CLO test was positive in 67% of vagotomy patients (20 of 30), while 50% (15 of 30) were H. pylori-positive by histology. The estimated sensitivity, specificity, PPV and NPV of the CLO test were 87%, 53%, 65% and 80%, respectively. H. pylori prevalence by histology was 50% in patients with vagotomy and 31% in those with gastrectomy (P = 0.0787). Recurrent ulcers were observed in 8/30 patients (27%) after vagotomy and in 10/72 patients (14%) after gastrectomy. Recurrent ulcer was documented in 6/15 H. pylori-positive patients with vagotomy (40%), and in one of 25 H. pylori-positive patients with gastrectomy (4%). This difference was significant (Fisher's exact test, P = 0.007, relative risk 5.091, 95% CI 0.819-31.64). CONCLUSION: The CLO test seems to be unreliable in diagnosing H. pylori in post-surgical stomach. The H. pylori prevalence is higher, although not significantly, in vagotomized patients compared with gastrectomized patients, and in this group is closely related to the presence of recurrent ulcer. So, at least in this group of patients, it is strongly recommended to look for and eradicate H. pylori.     

Evaluation of 13C-urea breath test to confirm eradication of Helicobacter pylori]

This study aimed to evaluate the effectiveness of the 13C-urea breath test (UBT) for assessment of Helicobacter pylori eradication after treatment. One hundred twenty six patients were enrolled with 85 receiving proton pomp inhibitor based triple therapy. They were underwent upper gastrointestinal endoscopy with biopsies for diagnosis and assessment of H. pylori infection using culture, histology, rapid urease test (RUT) and 13C-UBT. Assessment of eradication needs to be performed 4 weeks or more after completion of treatment. Breath samples were taken 15 minutes after the ingestion of 100 mg 13C-urea. Breath samples were analyzed on a mass spectrometer system. The gold standard for H. pylori infection was a positive culture or positive histology + positive RUT; negative for infection was defined as negative results of all three biopsy tests. Based on ROC curves, the most appropriate cut-off value for diagnosis of H. pylori infection was identified as 2.5/1000, which provided 96.2% sensitivity, 100% specificity, and 96.8% accuracy as judged by the gold standard. However, when confirming the eradication of H. pylori, it was 3.5/1000, which provides for 100%, 95.8%, and 96.5%, respectively. Ten patients (11.8%) had delta13C values that were 2.5-5.0/1000 4-12 weeks after therapy. Eight patients were considered cured of H. pylori infection, and 2 were considered to still have H. pylori infection following 13C-UBT, serology, and H. pylori specific antigen test. The false-positive rate of 13C-UBT was 9.4% (8/85). When the grey zone of 13C-UBT was set at a level of 2.5 to 5.0/1000 (2.5 > : negative, 5.0 < or = : positive) after eradication therapy, the sensitivity and specificity of 13C-UBT was 100% and 98.4% compared to the gold standard. It was concluded that to avoid false-positive results of 13C-UBT, the grey zone of 13C-UBT needs to be set at a level of 2.5 to 5.0/1000; thus improving the accuracy of test for the assessment of eradication of H. pylori infection.     

Quantitative correlation of Helicobacter pylori stool antigen (HpSA) test with 13C-urea breath test (13C-UBT) by the updated Sydney grading system of gastritis

BACKGROUND/AIMS: Helicobacter pylori (H. pylori) infection has a causative relationship with various gastrointestinal disorders. 13C-urea breath test and H. pylori stool antigen test are two valuable noninvasive tests for detecting H. pylori infection. Since the bacterial load of H. pylori in the stomach and the resulting severity of gastritis are important in validating the status of H. pylori infection, we would like to investigate the relative diagnostic accuracy of 13C-urea breath test and H. pylori stool antigen test with respect to the severity of gastritis. METHODOLOGY: The H. pylori statuses of 62 consecutive patients were evaluated by five tests, i.e., culture, histology, biopsy urease test, 13C-urea breath test, and H. pylori stool antigen test. Gastritis was graded by the updated Sydney system. H. pylori status was defined as positive when the culture was positive or the concordance of positivity of two of the other four tests. RESULTS: Thirty-five patients (56%) were H. pylori positive. The accuracy of H. pylori stool antigen test and 13C-urea breath test were 92.6% and 100%, respectively. There was a positive correlation between the level of delta 13CO2 of the 13C-urea breath test and the optical density value of enzyme immunoassay of the H. pylori stool antigen test (Rho = 0.758, P < 0.001). Both the level of delta 13CO2 of 13C-UBT and the optical density value of enzyme immunoassay of the H. pylori stool antigen test correlated well with the separate score of the density of H. pylori (P < 0.001, each) and the inflammatory activity (each P < 0.001). CONCLUSIONS: Both the 13C-urea breath test and H. pylori stool antigen test are effective non-invasive methods to detect the status of H. pylori infection with respect to correlation with the density of H. pylori and inflammatory activity of gastritis.     

~(14)C-呼气试验检测幽门螺杆菌感染

本文应用国产~(14)C-呼气试验(~(14)C-UBT)试剂检测幽门螺杆菌(Hp)。同时应用病理组织染色、尿素酶试验、细菌培养和血清 ELISA 技术等方法与之进行比较。117例病人中 Hp 阳性率为47.9%(56/117),~(14)C-UBT的敏感性与特异性分别为94.6%和93.4%。~(14)C-UBT 由于相对于胃镜依赖的方法而言创伤性大大降低,是目前检测 Hp 感染,尤其是药物治疗后复查时的首选方法。     

门脉高压性胃病与幽门螺杆菌相关性研究

为了解门脉高压性胃病(PHG)与幽门螺杆菌(HP)的关系,采用尿素酶试验、血清HP抗体检测和14C呼吸试验等方法检测50例肝硬化PHG患者HP的感染率,并与非PHG肝硬化(NPHG)、十二指肠球部溃疡(DU)、功能性消化不良(FD)三组患者比较.PHG组HP感染率为36%,与NPHG组(38%)、FD组(44%)分别比较差异无显著性(P＞0.05),与DU组(94%)比较差异有显著性(P＜0.01).说明HP感染对PHG发病影响不大.