Comparison of an enzyme immunoassay for the detection of Helicobacter pylori antigens in the faeces with the urea breath test.

BACKGROUND: Current diagnostic tests for Helicobacter pylori are invasive (endoscopy) or indirect (urea breath test, serology). AIMS: To evaluate a new enzyme immunoassay (EIA) which detects H pylori antigens in faeces, by comparing its sensitivity and specificity in children with the (13)C urea breath test (UBT). METHODS: A total of 119 children underwent a UBT and provided a faecal sample for antigen testing within seven days. After an overnight fast each child provided a pretest breath sample, and samples at 30 and 40 minutes after ingestion of 100 mg (13)C labelled urea. (13)C enrichment of breath was measured by isotope ratio mass spectrometry. Faeces were stored at -70 degrees C until antigen testing, using the EIA. Samples were read spectrophotometrically at 450 nm and results were interpreted using recommended cut offs of optical density <0.14 as negative, >/=0.16 as positive, with >/=0.14 and <0. 16 representing equivocal results. Sensitivity and specificity were calculated using the manufacturer's cut off compared with UBT. RESULTS: Sensitivity and specificity were 88% and 82%, respectively. Negative and positive predictive values were 97% and 58%. CONCLUSIONS: The EIA is an alternative, non-invasive, and easy to use method for the detection of H pylori in children. Its high negative predictive value suggests a role in screening out uninfected children.     

Comparison of invasive and non-invasive tests diagnosis and monitoring of Helicobacter pylori infection in children

BACKGROUND: There are few reports which the tests used for diagnosing Helicobacter pylori infection and monitoring its eradication in children. STUDY AIMS: Prospective evaluation of invasive (gastric histology, rapid urease test [RUT]) and non-invasive (stool antigen [FemtoLab H. pylori], urea breath test [UBT]) tests in the diagnosis of H. pylori infection and post-treatment eradication in children and adolescents. METHODS: Ninety-two patients (50 male, 42 female) referred for upper gastrointestinal endoscopy were prospectively enrolled. UBT was performed and stool specimens collected for monoclonal enzyme immunoassay for H. pylori antigen (FemtoLab) 1 to 4 days before endoscopy. H. pylori in gastric biopsies was evaluated by RUT and staining with hematoxylin-eosin and giemsa. Eradication therapy was given to children with abdominal pain and H. pylori gastritis. FemtoLab H. pylori and UBT were repeated 6 weeks after the end of triple therapy. RESULTS: Histology identified H. pylori in 49 of 92 (53%) subjects. Concordance between histology and RUT was found in 78 of 92 children. FemtoLab H. pylori was positive in 41 of 78 (52.6%) children with sensitivity, specificity, positive and negative predictive values of 97.5%, 94.7%, 95.1% and 97.3%, respectively. For UBT, these values were 100%, 96.9%, 97.5% and 100%, respectively. Twenty-six of 36 patients who received triple therapy returned for eradication evaluation. Tests for H. pylori antigen in stool were positive in 10 of 26 and for UBT in 11 of 26. CONCLUSION: Stool antigen (FemtoLab) and UBT were equally effective in diagnosing and confirming eradication of H. pylori infection in children.     

Accuracy of serology and 13C-urea breath test for detection of Helicobacter pylori in children

BACKGROUND: Indirect noninvasive methods, such as the 13C-urea breath test and serology, can be useful for the detection of Helicobacter pylori infection in children. We analyzed retrospectively the diagnostic accuracy of these two methods. PATIENTS AND METHODS: Between September, 1989, and October, 1996, H. pylori status was determined in 139 children by means of culture and histologic study of gastric biopsies. We performed 146 13C-urea breath tests and serologic assays (Cobas core; Roche). RESULTS: H. pylori infection was detected in 91 of 139 (65%) children. The 13C-urea breath test was discordant with H. pylori status in 4 of 146 tests; serology was discordant in 24 and indeterminate in 7 of 146. The 13C-urea breath test was more sensitive than serology (98% vs. 79%, P < 0.01) but comparable in specificity (96% vs. 92%). The serology yielded false negative results more often in children younger than 5 years of age (P < 0.05). CONCLUSIONS: The 13C-urea breath test is more reliable than serology for the detection of active H. pylori infection in children. Below 10 years of age serology is insufficiently sensitive for clinical purposes, whereas the 13C-urea breath test remains a reliable test.     

Helicobacter pylori and nonulcer dyspepsia in childhood: clinical pattern, diagnostic techniques, and bacterial strains

BACKGROUND: This is a report of the results of a multicenter study performed in children with dyspepsia from five pediatric centers in Puglia, a region in southern Italy. In the study, clinical features of Helicobacter pylori infection, the reliability of diagnostic techniques, and the involvement of bacterial strains were examined. METHODS: Fifty-three outpatients with dyspepsia enrolled in our study and compiled a diary recording clinical symptoms in patients before they underwent the following diagnostic techniques: endoscopy, biopsy for histologic analysis, rapid urease test, 13C urea breath test, serology specific for immunoglobulin (Ig)G and anti-CagA and VacA. RESULTS: H. pylori showed a prevalence of 30.2% (n = 16). Histologic positivity was seen in all patients at the antral level (H. pylori-associated chronic gastritis). In the gastric body, bacterial chronic active gastritis was present only in six patients (H. pylori-associated chronic pangastritis). Clinical evaluation showed a significant difference in favor of subjects positive for H. pylori only for epigastric burning and/or pain (p < 0.001). The comparison of results of diagnostic tests, using histology as the gold standard, showed sensitivity and specificity of more than 93% for 13C urea breath test and more than 85% for rapid urease test and serology. Anti-CagA antibodies were found in 64.3% and anti-VacA antibodies in 42.8% of H. pylori-positive patients. CONCLUSIONS: H. pylori prevalence in children with dyspepsia from the geographic area studied is comparable with that found in other developed countries. Approximately 50% of the studied patients were infected by cytotoxic strains. The urea breath test was the most reliable noninvasive diagnostic tool and is suitable for routine use, although endoscopy with histologic assessment remains the definitive investigation and is particularly important in patients with positive serology for CagA and VacA. Finally, the frequency of aggressive strains in our region seems to affect the clinical pattern; this emphasizes the importance of definitive diagnosis in children and offers a new role for serology.     

Evaluation of stool antigen test for Helicobacter pylori infection in asymptomatic children from a developing country using 13C-urea breath test as a standard

OBJECTIVE: Prevalence of asymptomatic Helicobacter pylori infection is very high in infants and children in developing countries. C urea breath test (UBT) is a reliable non-invasive diagnostic test for H. pylori infection in children that avoids invasive endoscopy. We compared a newly introduced H. pylori stool antigen test (with a high sensitivity and specificity in symptomatic children) with UBT in asymptomatic children mostly 1-5 years old, from a population with a high prevalence of infection. METHOD: Eighty six asymptomatic children (42 boys and 44 girls) were tested for H. pylori infection using the UBT and a stool antigen test (HpSA) based on a sandwich enzyme immunoassay for antigen detection. RESULTS: Forty five of the eighty-six (52.3%) children tested positive for H. pylori using the breath test. In 34 of these forty-five children, H. pylori antigen was detected in stool (sensitivity = 75.6%, 95% CI = 63 to 88%). Of the 50 of 86 (58%) children positive by HpSA test, 34 were positive for breath test. Of the 41 children with negative UBT test 25 were negative for stool antigen test (specificity = 61%, 95% CI = 46 to 76%). CONCLUSION: The sensitivity and specificity of the new stool antigen test are lower in asymptomatic children with high H. pylori prevalence rate compared to those reported for children with gastrointestinal symptoms. Its usefulness is limited for diagnosis in an asymptomatic child with H. pylori infection.     

Contribution of the 13C-urea breath test to the detection of Helicobacter pylori gastritis in children.

Serology, 13C-urea breath test, histology, Campylobacter-like organism testing, and culture were performed in 95 consecutive children to evaluate the contribution of these tests to the detection of Helicobacter pylori infection. In analyses considering any combination of three positive tests as "gold standard" for diagnosing H pylori infection, 26 children were Helicobacter positive (27%), which is only one patient more than the number of children with only a positive culture. The accuracy of culture was excellent when "any combination of three positive tests" was used as the gold standard (sensitivity 96%, specificity 100%, positive predictive value 100% [false positivity 0%], negative predictive value 99% [false-negative results 1%]). The results of invasive and noninvasive tests were comparable. When culture was considered as "gold standard," the sensitivity of serology and 13C-urea breath test was 96%; the specificity was 96% and 93%, respectively; the positive predictive value was 89% and 83% (false-positive results in 11% and 17%); and the negative predictive value for both was 99% (false-negative results in 1%). It is concluded that culture can be used as gold standard, but that non-invasive tests such as serology and/or 13C-urea breath test can be used to diagnose H pylori infection in children, since each has at least 95% sensitivity and 92% specificity.     

Helicobacter pylori infection in pediatrics. Present knowledge and practical problems

Helicobacter pylori (H. pylori) infection is acquired in childhood, earlier in developing countries, as a consequence the prevalence of infection is higher in developing countries (70%) than in developed countries (5-15%). H. pylori infection spreads from person-to-person, however the precise mode of transmission (oral-oral, fecal-oral or gastro-oral routes) is as yet, not known. Diagnosis of H. pylori infection can be performed with both invasive endoscopic-based tests, or non-invasive tests, mainly by measurement of IgG antibodies against the bacterium in serum samples or by measurement of 13CO2 in expired air (13C-urea breath test). In clinical practice endoscopy and biopsy is recommended before treatment to determine the presence and the degree of gastritis or ulcer. However, endoscopy is a complicated procedure in children and diagnosis of infection can be based on a non-invasive test. The association of H. pylori infection with recurrent abdominal pain seems evident in a subgroup of children with endoscopic features of gastritis, ulcer or hemorrhage. There is an increasing interest in the extraintestinal manifestations of H. pylori infection in children, i.e. iron-deficiency anemia, growth retardation and migraine, but this domain remains controversial. Since infection at a young age is believed to result in chronic atrophic gastritis and gastric cancer in adult life, it is logical to consider a future massive programme of eradication and immunization. Regimens suggested for H. pylori eradication are a combination of inhibitors of gastric acid secretion plus two antibiotics for 7-10 days.     

One week treatment for Helicobacter pylori infection

Helicobacter pylori is associated with primary antral gastritis, duodenal ulceration, and gastric cancer. Current regimens for treating infection in children using bismuth and antibiotics for two to six weeks are cumbersome. The aim of this study was to evaluate a one week course of treatment. All children undergoing endoscopy were assessed for the presence of H pylori by culture, histology, rapid urease test, and 13C urea breath test. Infected children received a one week course of colloidal bismuth subcitrate 480 mg/1.73 m2/day (maximum 120 mg four times a day), combined with metronidazole 20 mg/kg/day (maximum 200 mg three times a day), and clarithromycin 15 mg/kg/day (maximum 250 mg twice a day). To optimise compliance, drugs were dispensed in a 'Redidose' box containing a compartment for each day, and subcompartments marked 'breakfast', 'lunch', 'dinner', and 'bedtime'. Compliance and side effects were assessed immediately after treatment. A urea breath test was performed at least one month after treatment. Twenty two children infected with H pylori were entered into the study; 20 of these took all doses; two children suffered significant side effects (diarrhoea and vomiting). H pylori was eradicated in 21 of the 22 children (95.45%; 95% confidence interval 77% to 100%). This study shows that H pylori infection in children can be cleared by a one week course of treatment.     

胃液实时聚合酶链反应检测儿童幽门螺杆菌及宿主基因型的临床研究

目的探讨胃液实时聚合酶链反应(real-time PCR)检测儿童幽门螺杆菌(HP)感染、克拉霉素敏感性和宿主CYP2C19基因代谢型方法的准确性,旨在寻求一种方便、快速、准确检测儿童HP感染,克拉霉素敏感性和CYP2C19基因代谢型的方法。方法选取2013年7月至2014年11月北京儿童医院消化科123例13C呼气试验检查阳性的胃炎或消化性溃疡患儿进行电子胃镜检查,胃镜下取胃黏膜并收集胃液标本。从胃液中提取DNA,然后通过聚合酶链式反应(PCR)扩增Rnase P酶和cag H以检测幽门螺旋杆菌的存在。通过PCR限制性片段长度多态性(PCR-RFLP)分别检测HP23SrRNA和宿主CYP2C19基因代谢型。研究共利用5对引物和9条探针进行HPcag H基因和23SrRNA基因,以及人Rnase P基因和CYP2C19*2、CYP2C19*3基因检测。将胃液结果与胃黏膜活检标本HP培养和E-test药敏试验及CYP2C19基因代谢型检测结果进行比较分析。结果以胃黏膜HP培养、E-test药敏试验及CYP2C19基因代谢型检测结果为金标准,胃液实时PCR检测HP感染诊断敏感度为100%...     

Accurate diagnosis of Helicobacter pylori infection by stool antigen test and 6 other currently available tests in children

Invasive and noninvasive tests have been developed for the diagnosis of Helicobacter pylori infection. Because H pylori infection is acquired in childhood and adolescence, accurate diagnosis of the infection in the pediatric population is important. We conducted a study to compare invasive tests: culture, biopsy urease test, histology, and polymerase chain reaction on gastric biopsy specimens, with noninvasive tests: serology, (13)C-urea breath test, and a new diagnostic modality, stool antigen test to diagnose H pylori infection. A total of 53 children with symptoms were enrolled in this study, and all had completed the 7 diagnostic tests for H pylori. All the diagnostic tests except serology were excellent methods of diagnosing H pylori infection in children; the diagnostic accuracy was as follows: stool antigen test 96.2%, biopsy urease test 96.2%, histology 98.1%, polymerase chain reaction 94.3%, culture 98.1%, (13)C-urea breath test 100%, and serology 84.9%. The stool antigen test, being highly sensitive and specific, will be potentially very helpful in diagnosing H pylori infection in children.     

Management and response to treatment of Helicobacter pylori gastritis.

Gastritis associated with Helicobacter pylori was present in gastric biopsies from 24/95 (25%) children and adolescents undergoing endoscopy for recurrent abdominal pain and upper gastrointestinal symptoms. H pylori associated gastritis occurred mainly in older children (8-16 years) and was significantly associated with low socioeconomic class and a family history of peptic ulcer disease. Antral nodularity was a common endoscopic finding in H pylori positive children. Eighteen children, all over 5 years of age, were treated with tripotassium dicitratobismuthate (De-Nol) for two months and ampicillin for two weeks. In 12 children follow up gastric biopsies were obtained six weeks after completion of treatment. In 9/12 (75%) children H pylori was eradicated, and gastritis improved.     

Evaluation of 13C-urea breath test and fecal antigen immunoassay to detect Helicobacter pylori infection in Gambian infants

Helicobacter pylori colonization was measured by [13C]-urea breath test in 198 Gambian infants and by fecal enzyme-linked immunosorbent assay in 52 of the 198 at ages 2, 5, and 12 months. By 12 months there was good concordance between tests; 33 of 44 (75%) test results were positive by enzyme-linked immunosorbent assay, and 29 of 44 (66%) test results were positive by urea breath test. H. pylori colonization is common among Gambian infants, and noninvasive tests can provide a reliable means of diagnosis.     

Breath test using a single 50-mg dose of 13C-urea to detect Helicobacter pylori infection in children

BACKGROUND: The 13C-urea breath test is an accurate, noninvasive method for the diagnosis of in adults. A dose of 75 to 100 mg of urea is generally used, especially in adults, but the optimal dose in children is still unknown. Our aim was to determine whether urea breath test performed with a single 50-mg dose of 13C-urea was sufficient and accurate for diagnosing infection in children. METHODS: Consecutive children 4 to 14 years of age undergoing upper intestinal endoscopy to evaluate symptoms of recurrent abdominal pain were prospectively included. Exclusion criteria included use of antibiotics or proton pump inhibitors during the last month, gastric surgery, and previous eradication therapy. Reference criteria for diagnosis of infection were based on histology, culture, and serology. Urea breath test (TAU-KIT; Isomed, S.L., Madrid, Spain) was performed as follows: citric acid (Citral pylori) dissolved in 100 mL of water was initially given. Ten minutes later, a baseline exhaled breath sample was collected, and thereafter 50 mg of 13C-urea dissolved in 50 mL of water was given. A second breath sample was obtained 30 minutes later. Breath samples were analyzed by isotope ratio mass spectrometry. The endoscopist, the pathologist, the microbiologist, and the person responsible for reading the serology and the urea breath test were all unaware of status by the other diagnostic methods. RESULTS: One hundred children were included (40% males; mean age, 9.2 +/- 2 years; mean weight, 33.9 +/- 12 kg). Based on the reference criteria, 45% were infected, 37% were not infected, and 18% were indeterminate. Sensitivity, specificity, positive predictive value, and negative predictive value were, respectively, 91% (95% confidence interval [CI], 79%-96%), 97% (95% CI, 86%-99%), 98% (95% CI, 87%-91%), and 90% (95% CI, 76%-96%). Positive and negative likelihood ratios were of 33 and 0.09. Any cutoff point between 2 and 14 delta units had the same high diagnostic accuracy. The area under the receiver operating characteristic curve was 0.94. No adverse effects were reported. CONCLUSION: Urea breath test using 50 mg of urea is sufficient and accurate for the diagnosis of infection in children. Use of a small test dose significantly lowers the cost of the test.     

Normalizing results of 13C-urea breath testing for CO2 production rates in children.

BACKGROUND: The 13C-urea breath test detects the presence of Helicobacter pylori from an enrichment of breath 13CO2, which, in turn, is critically dependent on the amount of dilution by endogenous CO2 production. The production of CO2 differs according to age (adults > children), sex (male > female) weight, and height. The cutoff value of 2.4 delta%(delta over baseline, DOB) for the 13C-urea breath test, defined in adults, does not take into account actual CO2 production. Therefore, this cutoff value (2.4 delta%) may or may not be appropriate for children. The purpose of this study was to determine a cutoff value that would provide accurate results in pediatric patients, independent of their differences in anthropometric parameters. METHODS: Estimates of CO2 production were combined with DOB values to calculate the host-dependent urea hydrolysis rate. RESULTS: Calculated as urea hydrolysis rate, the cutoff range for adults was 10.4 to 10.9 microg/min. Individual ranges were concentric (men, 9.6-10.9 microg/min; women, 8.5-12.2 microg/min). Results in studies of 312 children show that a urea hydrolysis rate of more than 10 m microg/min may also be appropriate to predict H. pylori infection. CONCLUSION: Calculating 13C-urea breath test values as urea hydrolysis rate removes the effect of individual anthropometric differences on test outcome and provides a single cutoff value for pediatric patients of all ages.     

Immunohistochemical detection of Helicobacter pylori infection in gastric biopsies of urea breath test-positive and -negative pediatric patients

Helicobacter pylori (H. pylori) is a common cause of gastritis in both children and adults, and its incidence increases every year. The aims of this study were to evaluate the histopathologic features of H. pylori gastritis and to compare immunohistochemical with histochemical [hematoxylin-eosin (HE) and Giemsa] staining of gastric biopsy specimens for the detection of H. pylori infection from urea breath test (UBT) (-) and UBT (+) children. Seventy-eight gastric biopsies from pediatric patients who were administered UBT were included in this study. Gastric biopsy specimens were evaluated histopathologically and graded according to the Sydney system. HE, Giemsa and immunohistochemical staining was performed for the identification of H. pylori. The frequency of H. pylori gastritis was higher in the antrum than corpus. All biopsies with H. pylori colonization showed chronic inflammation with activity. By using immunohistochemical method, coccoid forms of H. pylori and spiral bacteria with low density were observed easily. With histochemical staining, 1/10 (10%) UBT (-) biopsies were H. pylori (+), while with immunohistochemical staining, 3 of the biopsies from UBT (-) patients were found to be H. pylori (+). Biopsies from 65 of 78 (83.3%) UBT (+) patients were H. pylori (+) with histochemical staining, but only 53 of these biopsies were found to be H. pylori (+) immunohistochemically. We conclude that immunohistochemical staining is more specific than histochemical staining and UBT for the detection of H. pylori infection.     

A rapid serologic test and immunoblotting for the detection of Helicobacter pylori infection in children

The gold standard for the diagnosis of Helicobacter pylori infection requires an endoscopic biopsy of gastric mucosa for histological examination, urease test and culture. Noninvasive serological tests are useful as a screening test for H. pylori infection. The aim of this study was to evaluate the performance of a rapid office-based serologic test, using immunochromatography ICM, and the immunoblotting for the diagnosis of H. pylori infection in Thai children. Eighty-two symptomatic children, 30 boys and 52 girls (mean age 9.2+/-3.8 years; range, 1.2-16.0 years) who had no previous treatment for H. pylori underwent upper endoscopy. Biopsies were obtained from the gastric body and antrum for histopathology and rapid urease test. Serum samples collected from all patients were tested for H. pylori IgG antibodies using ICM (Assure H. pylori Rapid Test, Genelabs Diagnostics, Singapore). Immunoblotting (HelicoBlot 2.1, Genelabs Diagnostics, Singapore) was tested in sera of 75 patients to detect antibodies to specific antigens of H. pylori. Positive H. pylori status was defined as positive for both histology and rapid urease test. Of 82 patients, 25 (30.5%) were H. pylori positive, 56 (68.3%) were H. pylori negative and one was equivocal. ICM assay yielded a positive result in 24 of the 25 H. pylori-positive patients (96.0%) and 3 of the 56 H. pylori-negative patients (5.4%). The immunoblotting yielded a positive result in all of 22 H. pylori-positive patients (100%) and in 2 of the 52 H. pylori-negative patients (3.8%). Obtained ICM's sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 96.0, 94.6, 88.9, 98.1 and 95.1%, with immunoblotting 100.0, 96.2, 91.6, 100.0, and 97.3%, respectively. The immunochromatographic and immunoblot tests are non-invasive, reliable and useful for the diagnosis of H. pylori infection in Thai children.     

Impact of Helicobacter pylori infection on growth of children: a prospective cohort study

OBJECTIVE: The aim of this study was to prospectively follow a cohort of children without Helicobacter pylori infection and to compare growth velocity in the children who become infected during follow-up with that of children who remained infection-free. METHODS: Three hundred forty-seven children in general good health, aged 12 to 60 months, who tested negative for H. pylori by the 13C-urea breath test, from three daycare centers in a lower-middle class borough of Cali, Colombia, were monitored for 2.5 years. Anthropometric measurements were performed every 2 months and breath tests every 4 months. Linear mixed models were used to analyze growth velocity in relation to onset of H. pylori infection. RESULTS: One hundred five (30.3%) children who were uninfected at the start of the study became infected during follow-up. Growth velocity in infected children was reduced by 0.042 +/- 0.014 cm/mo (P = 0.003) (approximately 0.5 cm/yr) after adjusting for age. The rate of deceleration in growth velocity was relatively constant over time. CONCLUSIONS: Among these lower-middle class children aged 12 to 60 months from a population with high prevalence of H. pylori infection, a new and sustained infection was followed by significant growth retardation.     

Helicobacter pylori colonization in early life

Helicobacter pylori infection is a major cause of upper gastrointestinal disease throughout the world. Colonization begins in childhood, although little is known about its age of onset, rate, or mode of colonization. Our aim was to identify the age of acquisition of H. pylori colonization in Gambian children. A cohort of 248 Gambian children aged 3 to 45 months was studied at intervals of 3 months for 2 years, using the 13C-urea breath test, specific IgM and specific IgG serology. The prevalence of positive breath tests rose from 19% at 3 months of age to 84% by age 30 months. Elevated specific IgG and IgM antibody levels were associated with positive breath tests, although there was discrepancy between breath test results and serology, particularly IgG serology, during the 1st year of life. Neither IgG nor IgM serology could be validated as reliable diagnostic tools for infant H. pylori colonization compared with the 13C-urea breath test. Reversion to negative breath test, in association with declining specific antibody levels, occurred in 48/248 (20%) of children. On the assumption that the 13C-urea breath test is a reliable index of H. pylori colonization, we conclude that the infection is extremely common from an early age in Gambian children. Transient colonization may occur. Previous studies relying on serodiagnosis may have significantly underestimated the true early prevalence of colonization in the developing world, where the target age for intervention studies is probably early infancy.     

Comparison of non-invasive tests to detect Helicobacter pylori infection in children and adolescents: results of a multicenter European study

OBJECTIVE: To compare the current non-invasive tests for Helicobacter pylori infection in children and adolescents. STUDY DESIGN: This multicenter, multinational study investigated the sensitivity, specificity, and positive and negative predictive values of four non-invasive tests: urea breath test (UBT), stool antigen test, and antibody detection in serum and urine, in comparison with biopsy-based tests. RESULTS: Of 503 patients included pre-treatment, 473 fulfilled the definition of H pylori status and among those 316 had results available for the four non-invasive tests (including 133 H pylori -positive patients). The specificity was excellent for all tests. The UBT had the best sensitivity in all age groups, followed by serology, stool test, and antibody detection in urine. A trend for better sensitivity with an increase in age was observed except for the stool test. The receiver operating characteristics (ROC) curves showed that sensitivity of serology, stool test, and urinelisa could be improved by changing the cutoff value. An inadequate storage of the specimens may explain the poor results of the stool test. CONCLUSION: The UBT appears to be an excellent test for diagnosis of H pylori infection for children and adolescents.     

13 C-urea breath test with infrared spectroscopy for diagnosing helicobacter pylori infection in children and adolescents

BACKGROUND AND OBJECTIVE: Studies support the accuracy of 13C-urea breath test for diagnosing and confirming cure of Helicobacter pylori infection in children. Three methods are used to assess 13CO2 increment in expired air: mass spectrometry, infrared spectroscopy, and laser-assisted ratio analysis. In this study, the 13C-urea breath test performed with infrared spectroscopy in children and adolescents was evaluated. METHODS: Seventy-five patients (6 months to 18 years old) were included. The gold standard for diagnosis was a positive culture or positive histology and a positive rapid urease test. Tests were performed with 50 mg of 13C-urea diluted in 100 mL orange juice in subjects weighing up to 30 kg, or with 75 mg of 13C-urea diluted in 200 mL commercial orange juice for subjects weighing more than 30 kg. Breath samples were collected just before and at 30 minutes after tracer ingestion. The 13C-urea breath test was considered positive when delta over baseline (DOB) was greater than 4.0%. RESULTS: Tests were positive for H. pylori in 31 of 75 patients. Sensitivity was 96.8%, specificity was 93.2%, positive predictive value was 90.9%, negative predictive value was 97.6%, and accuracy was 94.7%. CONCLUSIONS: 13C-urea breath test performed with infrared spectroscopy is a reliable, accurate, and noninvasive diagnostic tool for detecting H. pylori infection.