[14C]Urea Breath Test Is Not Sensitive for Detection of Acute Helicobacter pylori Infection in Rhesus Monkeys (Macaca mulatta)

The urea breath test is sensitive and specific for detection of chronic infection with H. pylori. We sought to determine the sensitivity of the [¹⁴C]urea breath test for detection of acute H. pylori infection using experimentally infected rhesus monkeys. Eighteen monkeys were inoculated with H. pylori. Serial [¹⁴C]urea breath tests and cultures of gastric biopsies were performed before and up to 10 weeks after inoculation. Cultures from all 18 monkeys were positive for H. pylori at each time point. The sensitivity of the [¹⁴C]urea breath test increased systematically from 43% at two weeks after inoculation up to 93% at 10 weeks after inoculation. Quantitative cultures of H. pylori showed a tendency to decline over time following inoculation. We conclude that the [¹⁴C]urea breath test is not sensitive for detection of acute H. pylori infection in rhesus monkeys until 10 weeks after inoculation. While this may reflect a gradual increase in bacterial load that was not detected by limited sampling, our data are not consistent with this hypothesis.     

Noninvasive detection ofHelicobacter pylori colonization in stomach using [11C]urea

Summary Helicobacter pylori is associated with chronic type B gastritis. Diagnosis can be made on gastric biopsy specimens and noninvasively using [¹³C]-or [¹⁴C]urea breath tests. Both breath tests require meticulous breath collection, and false positive results are possible from urease producing oral-pharyngeal flora. We used [¹¹C]urea, a positronemitting radionuclide allowing dynamic imaging, to measure metabolism of urea in the stomach of biopsy documentedH. pylori-positive patients. [¹¹C]urea was synthesized from¹¹CO₂ produced using a Van de Graaff accelerator and administered with [^99mTc]DTPA to control for loss of radioactivity via gastric emptying. Images were obtained externally by gamma camera every minute and¹¹CO₂ was monitored in the breath continuously for 30 min. AnH. pylori-positive patient exhibited a^99mTc/¹¹C activity ratio of 2.1 in the stomach 10–20 min following administration, compared to a 11 ratio in a negative control, indicating metabolism of urea to¹¹CO₂ with subsequent diffusion of¹¹C activity out of the stomach. The¹¹C activity in the breath peaked at 10–20 min in theH. pylori-positive patients. The short half-life of carbon-11 (20.4 min) alleviates radiation safety concerns and results in low absorbed radiation doses to patients.This work was supported in part by the National Science Foundation (grant R11-8110671), the Commonwealth of Kentucky through the Kentucky EPSCoR program, a grant from the University of Kentucky Association for Medical Research, and the Veterans Administration.     

Clinical significance of oral urease in diagnosis of Helicobacter pylori infection by [13C]urea breath test

This study was performed to evaluate the effect of oral flora on [¹³C]urea breath test in detecting H. pylori infection and find an optimal method and timing for sample collection. Forty-five volunteers were included in this study. The [¹³C]urea breath test was performed using mouthwash, endoscopic administration, and conventional methods. According to the receiver-operating characteristic curves, the earliest optimal time for discriminating H. pylori-positive and H. pylori-negative patients was at 25 min with the mouthwash method with 78% sensitivity and 82% specificity, at 2 min with the endoscopic administration method with 100% sensitivity and 100% specificity, and at 6 min with the conventional method with 100% sensitivity and 95% specificity. The study shows a significant effect of oral urease on the results of the [¹³C]urea breath test. The timing of sampling collection can be shortened to 6 min with the conventional method or to 2 min through endoscopic administration.     

Accuracy of Stool Antigen Test in Posteradication Assessment of Helicobacter pylori Infection

Our aim was to evaluate the accuracy of HpSA test in the diagnosis of Helicobacter pylori infection after the end of eradication therapy. In all 106 H. pylori-positive patients (55 men and 51 women, mean age 51 years, range 19–82) were treated with a course of eradicating regimen. [¹³C]Urea breath test (UBT) and HpSA were performed four weeks after stopping the treatment. The diagnostic accuracy of HpSA was evaluated in comparison with the results of [¹³C]UBT. In 90 patients (85%) H. pylori was eradicated according to [¹³C]urea breath test. After eradication, sensitivity of HpSA was 87.5%, specificity 95.5%, positive predictive value 77.8%, negative predictive value 97.7%, and diagnostic accuracy 94.3%. HpSA is a valuable test in the posteradication assessment of H. pylori infection.     

δ13CO2 Excretion and Expression of Dyspeptic Symptoms in Patients Evaluated for Helicobacter pylori Infection by [13C] Urea Breath Test

Previous studies showed that either the urease activity possessed by H. pylori and the bacterial load may influence the results of the [¹³C] urea breath test. However, the correlation between urease activity and dyspepsia is unclear. The aim of our study was to evaluate whether the urease activity of the gastroduodenal tract may influence the severity of dyspeptic symptoms. In all, 2520 dyspeptic patients (1109 men, 1411 women; mean age 47 ± 16 years) without gastroesophageal reflux disease, diabetes, vascular disorders, liver and biliary tract diseases, and tumors of the gastrointestinal tract and with a normal appearing abdominal ultrasonography were enrolled. All these patients underwent a [¹³C] urea breath test and filled out a questionnaire on dyspeptic symptoms. Subjects were divided in five different groups according to delta over baseline (DOB) values (group 1 < 3.5, group 2 = 3.5–6; group 3 = 6.1–11, group 4 = 11.1–23, group 5 > 23.1). The prevalence and intensity of dyspeptic symptoms were compared among groups. In all, 1688 patients (67%, 928 females and 760 males; mean age 48 ± 15 years) were H. pylori-positive. The chi-squared test and analysis of variance showed increase of frequency and intensity of each dyspeptic symptom according to DOB values. In conclusion, Dyspepsia may parallel gastric urease activity. However, whether higher DOB values are related to higher bacterial load or, alternatively, to the presence of particular H. pylori strains able to produce larger amounts of urease is uncertain.     

Gastric emptying andHelicobacter pylori infection in duodenal ulcer disease

The pathogenetic link betweenHelicobacter pylori gastritis and duodenal ulcer is still unknown. Fast gastric emptying of liquids might be important in the pathogenesis of gastric metaplasia of the duodenum and duodenal ulcer through an increased exposure of the duodenum to gastric acid. InH. pylori-infected subjects, an abnormal gastric emptying could affect urea breath test results and correlate with the histological gastritis. This study was performed to evaluate the gastric emptying of liquids in duodenal ulcer patients withH. pylori infection and the possible relation between the bacterial load, gastric emptying, and urea breath test results. Seventeen duodenal ulcer patients withH. pylori gastritis and 15 healthy volunteers were studied by a combined [¹⁴C]octanoic acid and [¹³C]urea breath test to evaluate gastric emptying rate andH. pylori status simultaneously. Endoscopy with antral biopsies was performed in all duodenal ulcer patients. Duodenal ulcer patients withH. pylori infection have a normal liquid gastric emptying that is unrelated with the histological severity of gastritis. The urea breath test results and the gastric emptying parameters do not correlate with histology. A significant correlation between the gastric emptying and the urea hydrolysis rate is found. It is concluded thatH. pylori infection in duodenal ulcer patients is not associated with abnormally fast liquid gastric emptying, and this finding should be taken into account when a causal link betweenH. pylori infection and duodenal ulcer disease is searched for. The correlation between gastric emptying and urea hydrolysis rate explains why no conclusions on intragastric bacterial load can be drawn from the urea breath test results.This study was presented in part as an oral communication at the Annual Meeting of the American Gastroenterological Association, May 1994, New Orleans, and published in abstract form inGastroenterology 106:A160, 1994.     

Selection of Lower Cutoff Point of [13C]Urea Breath Test Is Helpful to Monitor H. pylori Eradication After Proton Pump Inhibitor-Based Triple Therapy

Our objectives were to test the efficacy of [¹³C] urea breath test (UBT) for H. pylori infection in patients before and after proton pump inhibitor (PPI) based triple therapy, and thus to trace the optimal cutoff value of UBT to monitor H. pylori eradication; and to analyze the histologic bacterial density and distribution of H. pylori in patients with equivocal UBT. A total of 441 dyspeptic cases patients enrolled and completed the study design, including 120 noninfected and 321 H. pylori-infected patients. All 441 cases had received the same protocol of UBT, in which the baseline and 15-min gas samples after ingestion of 100 mg ¹³C-labeled urea were analyzed for excess ¹³CO₂/¹²CO₂ ratio (ECR). In addition, a first endoscopy was performed in each patient to evaluate the initial status of H. pylori by culture and histology. Of the 321 H. pylori-infected patients, 286 received a second endoscopy and a second UBT six weeks after completing any one of four regimens of the PPI-based triple therapy to document the success of H. pylori eradication. During both sessions of endoscopy, topographic gastric biopsies for histology were sampled to evaluate the distribution and density of H. pylori. Based on the diagnostic standard by culture and histology, the sensitivity and specificity of the first UBT achieved most optimally was 97.5% and 96.7%, respectively, by setting the cutoff point of ECR at 4.0. In contrast, using the same cutoff point of 4.0, the sensitivity and specificity of the second UBT in patients after therapy achieved just 80% and 97.6%, respectively. By applying cutoff points downward of 4.0, 3.5, 3, and 2.5 for the second UBT, the sensitivity was elevated to 80%, 82.8%, 88.6%, and 94.3%, respectively, while the specificity was preserved at more than 95.2%. The overall eradication rate of H. pylori was 87.8% (251/286). Seven of 35 patients with failure of therapy had equivocal ECR at the second UBT (range 2–5), and this accounted for the false negative result. All seven patients had low bacterial densities, and three patients had bacteria distributed only in high body near the cardia. In conclusion, selection of a lower cutoff value of ECR at 2.5 is helpful to maintain the diagnostic accuracy of UBT for monitoring the H. pylori eradication. The equivocal ECR of UBT after therapy would be related to the low bacterial load and its distribution.     

Quantitative noninvasive testing for Helicobacter pylori does not predict gastroduodenal ulcer disease

Background: Helicobacter pylori is strongly associated with gastric and duodenal ulcer disease. However, the diagnosis of gastroduodenal ulcers requires an endoscopic or radiographic examination. In this study, we attempted to establish a relationship between the magnitude of [¹³C]urea breath test results or serum H. pylori IgG levels and endoscopic findings in H. pylori-infected individuals. Methods: Patients who had undergone endoscopy and had a positive [¹³C]urea breath test and/or positive H. pylori IgG serology were identified. Endoscopic diagnoses included duodenal ulcer, gastric ulcer, nonulcer dyspepsia, and others. Results of 6% or greater on the [¹³C]urea breath test was defined as positive for H. pylori infection. H. pylori IgG serology was determined by an enzyme linked immunosorbent assay with values of greater than or equal to 1.0 being seropositive. Results: One hundred seventy-five patients were seropositive (mean = 3.01 ± 1.58). One hundred sixty-eight patients had a positive [¹³C]urea breath test (mean = 25.43 ± 16.90). One hundred fifty-five patients were common to both the groups. Statistical analysis did not reveal any relationship between quantitative [¹³C]urea breath test results or H. pylori IgG values and endoscopic diagnoses. Conclusion: The magnitude of [¹³C]urea breath test or H. pylori IgG serology cannot be used to predict the presence or absence of gastroduodenal ulcer disease. (Gastrointest Endosc 1996;44:679-82.)     

Diagnosis ofCampylobacter pylori gastritis

Campylobacter pylori is a bacterium that inhabits gastric mucosa. It causes chronic active gastritis and is highly associated with duodenal ulcer.Campylobacter pylori has a urease enzyme (not present in man), which allows diagnosis by a [¹⁴C]urea breath test. We compared two noninvasive tests, the breath test and serum ELISA, to biopsy and histologic diagnosis. Twenty-two patients who underwent gastroduodenoscopy for evaluation of possible peptic ulcer disease entered the study. The breath test detected the organism in eight of eight patients biopsy-positive for the organism (sensitivity 100%). The breath test was negative in 12 of the 14 patients who were biopsy-negative (specificity 86%). The ELISA was performed in 14 patients. It was positive in 5 of 5 patients biopsy-positive for the organism (sensitivity 100%) and negative in 7 of 9 patients who were biopsy-negative (specificity 78%). We conclude that both the ELISA and the [¹⁴C]urea breath test are excellent noninvasive methods to detectCampylobacter pylori. However, only the breath test is suitable for following the response to treatment, as it detects the presence of the organism rather than an immune response to it.The statistical analysis was performed by the Clinfo computer program.     

Best cut‐off values for [14C]‐urea breath tests for Helicobacter pylori detection

Background: The ‘test and treat’ strategy for Helicobacter pylori is recommended in dyspeptic patients under 55 years of age with no alarm symptoms. Reliable non‐invasive tests are therefore needed. The aim of this study was to assess the pre‐ and post‐treatment accuracy of a low dose (1?μCi [37kBq]), short collecting time [ ¹⁴ C]‐UBT (urea breath test) in diagnosing H pylori infection, examining different methods to analyse the best cut‐off points. Methods: The study included 119 patients. Endoscopy and [ ¹⁴ C]‐UBT were performed in the pre‐ and post‐treatment setting. [ ¹⁴ C]‐UBT results were expressed in three different ways: 1) the measured disintegrations per minute (dpm) at sample time, 2) the difference (D) in dpm between sample time and the dpm at T ₀ , 3) the ratio of dpm at sample time to dpm at T ₀ . Results: Seventy‐six out of the 119 patients (63.9%; 95% CI: 54.9 to 71.9) were infected. Seventy‐three (96%) patients completed the follow‐up. The most accurate results in both pre‐ (sensitivity 95.9%; specificity 97.7%) and post‐treatment (sensitivity 90.9%; specificity 100%) were obtained using the difference (D) in dpm between sample time at T ₀ and at T _12.5 . Conclusion: A low dose [ ¹⁴ C]‐UBT, with a short collecting time, is a reliable method to evaluate H. pylori infection in both the pre‐ and post‐treatment setting.     

Impact of long-term ranitidine and pantoprazole on accuracy of [13C]urea breath test

No previous study has analyzed the impact of long-term antisecretory drugs on the precision of [¹³C]urea breath test (UBT). We assessed the rate of UBT conversion from positive to negative results during 60-day therapy with standard doses of ranitidine and pantoprazole. For this purpose, we recruited 60 dyspeptic patients with H. pylori infection ascertained on the basis of the concomitant results of CLO-test, histology, and UBT. Our patients were randomly assigned to receive ranitidine 300 mg at night or pantoprazole 40 mg in the morning for 60 days. UBT was performed at baseline and on days 14, 30, and 60, while patients were still taking antisecretory drugs. Patients with false-negative UBT on day 60 repeated the test every 3 days until conversion. After overnight fasting, duplicate breath test samples were taken from each patient before and 30 min after ingestion of 75 mg [¹³C]urea dissolved in 150 ml of 0.033 mol/liter citric acid. Four patients dropped out of the study. Both drugs induced similar false-negative UBTs on day 14 of dosing (P = 0.5). Afterwards, the three false-negative UBTs in the ranitidine group again became positive during therapy and particularly on day 30 of dosing. Of the four false-negative UBTs in the pantoprazole group at day 60, one became positive after 3 and three after 9 days of therapy cessation. Our findings show that the long-term use of ranitidine and pantoprazole at standard doses has different effects on the results of UBT. In the pantoprazole group patients again became positive within 3–9 days after stopping 60-day therapy, whereas in the ranitidine group patients reverted to positive on day 30 of dosing while they were still on treatment and this was likely due to development of tolerance. Therefore, patients taking pantoprazole need at least a 10-day withdrawal before UBT testing, while those taking ranitidine for at least 30 days can undergo UBT without the necessity of a wash-out period.     

More economic 25 mg 13C-urea breath test can be effective in detecting primary Helicobacter pylori infection in children

Background and Aim: The high cost of the ¹³C‐urea breath test (UBT) limits its wide application for both epidemiological and clinical studies for diagnosing Helicobacter pylori infection. This study examined if a lower‐dose UBT, applying 1 mg/kg of bodyweight (maximum 25 mg, UBT²⁵), could introduce cost savings while preserving high diagnostic yields for primary H. pylori infection. Methods: Children aged less than 16 years were recruited after obtaining consent. Those children with administration of antibiotics or proton pump inhibitors within 1 month of the tests were excluded. Positive tests for both the UBT with 50 mg urea (UBT⁵⁰) and the H. pylori stool antigen (HpSA) were qualifying criteria for H. pylori infection. Negative results for both indicated non‐infection. The UBT²⁵ was conducted 1 week after the UBT⁵⁰. The cut‐off points for the UBT²⁵ ranging from 2δ to 5δ were examined for their sensitivity, specificity and accuracy rates. Results: A total of 153 children were recruited (55% male; mean age 9.1 ± 3.5 years). Both the UBT⁵⁰ and HpSA test were positive in 18 (13.1%) and negative in 119 children, respectively. The sensitivity and specificity of the UBT²⁵ were optimally achieved at 88.9% (95% confidence interval [CI]: 71.4–100) and 95.0% (95% CI: 91.1–99.9), judged with a cut‐off point at 3.5δ. The diagnostic accuracy was significantly higher for children older than 7 years than for those younger than 7 years (98%vs 85%, P = 0.009). Conclusion: Lower‐dose UBT titration by bodyweight can cut costs while maintaining a highly reliable method to screen primary H. pylori infection in children older than 7 years, which is generally beyond school age.     

Helicobacter pylori Recurrence and Infection Rate in Israeli Adults

Introduction In developing countries the recurrence rate of Helicobacter pylori after successful eradication therapy is as high as 42%, while in developed countries it is estimated to be less than 3%. Such figures are very important in terms of determining clinical strategy and outcome. Aim To estimate the recurrence rate of H. pylori in Israel using the database of the "Central H. Pylori Laboratory of Clalit Health Services". Methods The database was searched for patients who had undergone the [¹³C]-urea breath test ([¹³C]-UBT) for validation of the successful eradication of H. pylori or for evaluation of dyspepsia 7 years previously and for whom the result had been negative. These patients were invited to participate in the trial, fill a symptom questionnaire and undergo another [¹³C]-UBT. Results A In total, 65 patients participated; of these, 26 patients had tested negative in the first ¹³CUBT, indicating the successful eradication of H. pylori (Group A), and 39 had been tested for dyspepsia (Group B). One patient in each group had a positive [¹³C]-UBT – 3.84% in Group A and 2.56% in Group B (non-significant difference, NS). The mean annual H. pylori recurrence rate was calculated to be 0.55% and 0.37% in Group A and Group B patients, respectively (NS). Conclusion Our results shown a very low re-infection or new infection rates in Israeli adults and are in line with other trials in developed countries; they do not support the a retesting program for patients after a successful eradication therapy.     

13C-Urea Breath Test in Helicobacter pylori Diagnosis and Eradication Correlation to Histology,Origin of ‘False’ Results,and Influence of Food Intake

Background: Which protocol is optimal for the ¹³C-urea breath test (UBT) for Helicobacter pylori detection is controversial. This study aimed to characterize a very simple UBT protocol for the clinical routine (two-point-analysis performed with 75 mg ¹³C-urea and citric acid) with special consideration of ‘false’ UBT results. Results: UBT was evaluated in reference to histology (Warthin-Starry). In mismatching results re-gastroscopy was performed. By UBT, 74 of 77 patients with H. pylori-positive histology were detected (sensitivity, 96%). The false-negative UBTs were due to low colonization densities during spontaneous H. pylori elimination or pyloric obstruction. Seven of 49 patients with negative histology had a positive UBT, but re-gastroscopy showed that all of them had a positive histology when multiple antral biopsy specimens were taken (UBT specificity, 100%). UBT correlated only weakly with H. pylori colonization density. No correlation was found between UBT and gastric neutrophil and lymphocyte infiltration. UBT reproducibility was excellent (93 of 94 in a 6-month period). Non-fasting conditions induced a shift to lower UBT results in H. pylori-positive and to higher UBT results in negative patients, resulting in 2 of 10 false-positive and 1 of 10 false-negative UBTs. Conclusion: This simple version of the urea breath test combines the highest sensitivity and specificity with excellent reproducibility. It is superior to histologic detection of H. pylori in the clinical routine and an optimal tool for monitoring H. pylori eradication. Fasting conditions are required for the test.     

Helicobacter pylori Infection Is Not Associated with Subclinical Hepatic Encephalopathy in Stable Cirrhotic Patients

The importance of ammonia-producing Helicobacter pylori infection as a cause of subclinical encephalopathy in cirrhosis was investigated. In addition, a single psychometric test that can reliably detect subclinical hepatic encephalopathy was sought. Out-patients with cirrhosis and no overt encephalopathy underwent [¹⁴C]urea breath testing once and psychometric testing on two separate occasions, with an intervening course of clarithromycin/omeprazole if they had subclinical encephalopathy (two of four psychometric tests abnormal). Subclinical encephalopathy was present in 27 of 69 patients (39%), and Helicobacter pylori infection in 14 of 69 (20%). There was no association between the two conditions (P = 0.769). Subclinical encephalopathy resolved in 75% of treated Helicobacter pylori-positive patients and 37.5% of treated Helicobacter pylori-negative patients (P = 0.285). Number connection test-B had high reproducibility among untreated patients (R = 0.655) and high correlation (P 0.01) with three surrogate gold standards. In stable cirrhotic patients, subclinical hepatic encephalopathy was found to: (1) have a high prevalence, (2) not be associated with Helicobacter pylori infection, and (3) be readily detected with the number connection test-B alone.     

Qualitative and quantitative clinical evaluation of the laser-assisted ratio analyser for detection of Helicobacter pylori infection by (13)C-urea breath tests

OBJECTIVES: Currently, the (13)C-urea breath test is the reference method for non-invasive diagnosis of Helicobacter pylori infection and therapy control. Therefore, new technologies have been developed to measure the ratio of (13)CO(2)/(12)CO(2) in breath. The laser-assisted ratio analyser (LARA) device is based on optogalvanic effects of the stimulated CO(2) molecules. DESIGN: In this study, the LARA system is prospectively compared to conventional isotope ratio mass spectrometry (IRMS) analysis of (13)C-urea breath tests. METHODS: The (13)C-urea breath test was used to screen 103 patients for H. pylori infection. Breath samples were analysed by LARA and IRMS techniques. RESULTS: Seven breath tests could not be analysed by the LARA system, one by IRMS. Out of the remaining 95 breath tests, 13 were positive for H. pylori infection (13.7%). In reference to IRMS analysis (with a cut-off of > 5 delta per thousand at 30 min), LARA produced one false positive and one false negative breath test result giving a sensitivity of 92.3% and a specificity of 98.8%. The mean difference in delta over baseline values between IRMS and LARA measurements was 2.02 delta per thousand +/- 5.48 delta per thousand. CONCLUSION: LARA allows the reliable qualitative evaluation of 13C-urea breath tests, but the quantitative results differ from IRMS findings.     

Usefulness of the [13C]-urea breath test for detection of Helicobacter pylori infection in fasting patients

Most of the reported [¹³C]-urea breath test procedures use a test meal, which is believed to assist in the spread of the [¹³C]-urea solution into the entire stomach, as results without a test meal may mainly reflect urease activity in the antrum. Yet, procedures for the [¹³C]-urea breath test and interpretation of the obtained ¹³C excess value have not been well established. We carried out the present study to validate the usefulness of the [¹³C]-urea breath test in fasting subjects and to establish cut-off values. [¹³C]-Urea breath tests were performed on 258 Helicobacter pylori-positive and 151 -negative subjects (247 H. pylori positive and 26 negative prior to any H. pylori cure treatment and 125 H. pylori negative and 11 positive after undergoing H. pylori cure treatment). The breath test procedure was performed under the following conditions: an 8 h fast, mouth washing before and after dosing, administration of 100 mg [¹³C]-urea, collection of breath sample in a plastic bag, a baseline and a 20 min sampling point and subject in a sitting position. Delta-¹³C at the 20 min sampling point in H. pylori-positive and -negative subjects was 31.0 ± 1.25 and 1.6 ± 0.11%o, respectively. Although the mean Δ¹³C value was greatest in duodenal ulcer or ulcer scar patients, there were no significant differences among mean Δ¹³C values in the various diseases. From Receiver Operator Characteristic curves and calculation of accuracy of the test, a cut-off value of 5.0%o is considered to be appropriate for diagnosis of H. pylori infection, which provides 96.7% specificity and 96.5% sensitivity, suggesting that the [¹³C]-urea breath test in the fasting state is as effective in detecting the presence of H. pylori as other reported methods.     

Comparison between the <Superscript>13</Superscript>C-urea breath test and stool antigen test for the diagnosis of childhood <Emphasis Type="Italic">Helicobacter pylori</Emphasis> infection

Background As noninvasive tests for Helicobacter pylori infection, the ¹³C-urea breath test (UBT) and stool antigen test have been widely used. In children, however, there are few studies reporting which test shows superior performance. The purpose of this study was to compare the ¹³C-UBT and stool antigen test for their accuracy in diagnosing H. pylori infection in children.Methods A total of 123 Japanese children, ages 2 to 17 years (mean, 12 years) who underwent gastric biopsies for H. pylori infection were studied. The diagnoses included gastritis (n = 55), gastric ulcer (n = 5), duodenal ulcer (n = 20), iron-deficiency anemia (n = 7), and other conditions (n = 36). The cutoff value of the ¹³C-UBT was defined to be 3.5. The stool antigen test was performed using the HpSA enzyme-linked immunosorbent assay (ELISA) (Premier Platinum HpSA). In 16 patients who received eradication therapy, the ¹³C-UBT and HpSA were repeated 2 months after treatment.Results Based on biopsy tests, 60 children were infected with H. pylori and 63 children were not. For the ¹³C-UBT, the sensitivity, specificity, and accuracy were 95.0% (95% confidence interval [CI], 86.1%–99.0%), 98.4% (95% CI, 91.5%–100%), and 96.4% (95% CI, 93.6%–99.9%), respectively. For the HpSA, the sensitivity, specificity, and accuracy were 98.3% (95% CI, 90.8%–100%), 98.4% (95% CI, 91.2%–100%), and 98.3% (95% CI, 96.0%–100%), respectively. There were no significant differences between the performance of these two tests. In the assessment of H. pylori eradication, the results of ¹³C-UBT and HpSA agreed with those of biopsy tests.Conclusions The ¹³C-UBT and the HpSA are equally accurate for the diagnosis of active H. pylori infection in Japanese children.Kazuie Iinuma, for the Japanese Pediatric Helicobacter study Group     

Significance of an exaggerated meal-stimulated gastrin response in pathogenesis of Helicobacter pylori-negative duodenal ulcer

The aim of this study was to clarify the pathogenesis of Helicobacter pylori-negative duodenal ulcer (DU) by investigating the meal-stimulated serum gastrin (SG) response. The subjects were 9 patients with H. pylori-negative DU, 28 H. pylori-positive DU, 11 H. pylori-positive volunteers, and 30 H. pylori-negative volunteers. Blood samples were taken before and after consumption of a test meal. The integrated 1-hr gastrin response (IGR) was taken to be the area under the SG time curve, calculated by the trapezoid method. H. pylori infection status was determined by histology, serology, and the [¹³C] urea breath test. The mean basal SG concentration was lower in the H. pylori-negative DU patients than in the H. pylori-positive DU patients, but an exaggerated IGR was observed in three patients (33.3%) with H. pylori-negative DU. In conclusion, our findings indicate that an exaggerated meal-stimulated gastrin response may contribute to the pathogenesis of H. pylori-negative DU.     

Comparison of two new rapid serology tests for diagnois of Helicobacter pylori infection in Chinese patients

Background. Rapid serology test is a simple and convenient way for diagnosing Helicobacter pylori infection. However, performances of these tests are usually less satisfactory than expected, particularly in developing countries.Aim. To evaluate the performances of two newly developed rapid serology tests for Helicobacter pylori infection.Patients. Consecutive Chinese dyspeptic patients undergoing upper gastrointestinal endoscopy.Methods. Gastric biopsies were obtained from antrum and corpus for rapid urease test and histological examination. Diagnosis of Helicobacter pylori infection was based on two or more positive results in rapid urease test, histology and [¹³C] urea breath test. Patients' sera were tested against two rapid serology tests: ASSURE Hp Rapid Test (Genelabs Diagnostics, Singapore) and SureStep (Applied Biotech, San Diego, CA, USA).Results. A total of 148 patients were evaluated and Helicobacter pylori infection was diagnosed in 78 (53%) patients by gold standard. The sensitivities of ASSURE Hp and SureStep were, respectively, 94% and 71 % (p=0.0003). Specificities of the two test kits were both 90%. The overall accuracy of ASSURE Hp was significantly higher than SureStep (92% versus 80%, P=0.004).Conclusion: Both rapid serology tests appear to be specific in diagnosing Helicobacter pylori infection in the Chinese populations. However, the ASSURE Hp test is more sensitive and accurate than the SureStep test.