粪便标本抗原检测诊断儿童幽门螺杆菌感染

目的 进行非侵入性粪便标本幽门螺杆菌抗原检测诊断儿童幽门螺杆菌(H.pylori)感染,并评价此试验方法的应用价值。方法：选择有上消化道症状的48例患儿为研究对象,采用H.pylori抗原检测试剂盒,以酶联免疫分析双抗体夹心法检测粪便H.pylori抗原,并与胃粘膜活检标本快速尿素酶试验、组织学、血清学试验作对比研究。结果：4种诊断试验诊断准确率分别为：粪便抗原试验95.8%,快速尿素酶试验95.9%,组织学97.9%,血清学83.7%。粪便抗原试验的特异度和敏感度分别为100%,93.6%。结论：粪便标本H.pylori 抗原试验诊断儿童幽门螺杆菌感染有较高的准确率、敏感性和特异性,为新的简便易行的非侵入性方法。     

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.     

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.     

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.     

Evaluation of a novel stool native catalase antigen test for Helicobacter pylori infection in asymptomatic North American children

Rapid immunochromatographic tests for Helicobacter pylori infection have been developed to allow "near-patient" testing. We therefore performed a pilot study to test a rapid immunochromatographic stool antigen test for the diagnosis of H. pylori infection in asymptomatic children. We tested stool specimens collected from children participating in a cohort study in the United States and Mexico. H. pylori-positive status was defined by positivity on at least 2 tests: a commercial H. pylori stool antigen enzyme immunoassay, an immunoglobulin G antibody enzyme immunoassay, and the C-urea breath test. Negative H. pylori status was defined by negative findings of all of these tests. Of 52 children (22 girls, 30 boys) 25 were H. pylori-positive, 19 H. pylori-negative, and 8 uncertain (eg, presumably negative; positive findings on 1 of the 3 noninvasive tests). The sensitivity and specificity of the new stool antigen test for those with definite H. pylori status were 100% (exact 95% CI 86.3%-100% and 82.4%-100%, respectively). This rapid stool antigen test may prove useful for point-of-care testing and epidemiological field studies. Larger prospective studies are needed in symptomatic and asymptomatic children for more precise estimates.     

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.     

Helicobacter pylori antigens in stool specimens of gastritis children before and after treatment

BACKGROUND: Various testing methods are successfully applied to the diagnosis of Helicobacter pylori infection, but noninvasive techniques are still needed for therapeutic monitoring, especially in children. In the search for new noninvasive techniques for the diagnosis of H. pylori infection, the authors evaluated an enzyme immunoassay for the detection of H. pylori antigen in stool (HpSA). METHODS: The authors studied 62 H. pylori-positive children with chronic gastritis and 45 control subjects. H. pylori infection was diagnosed using cultures and histology of gastric biopsy specimens and a stool antigen test before treatment (clarithromycin, amoxicillin, omeprazole for 7 days) and 4 weeks to 6 weeks after treatment. RESULTS: Before therapy, antigen in stool was detected in 55 of 62 H. pylori-positive patients, which indicates that the sensitivity of the HpSA test was 88.7%. Of the 45 control subjects (with negative culture and histology results), 43 had negative results for H. pylori in the stool test (specificity, 95.5%). After completion of therapy, eradication was obtained (and confirmed by culture and histology) in 53 of the 62 H. pylori-positive children (85.5%). Four weeks to 6 weeks after eradication therapy, the sensitivity, specificity, positive predictive value, and negative predictive value of the stool antigen (HpSA) test were 88.9%, 96.2%, 80%, and 98%, respectively. CONCLUSIONS: The accuracy of the HpSA test for the detection of H. pylori in human stool 4 weeks to 6 weeks after treatment is comparable with the accuracy of the culture results. The stool antigen (HpSA) test was found to be a useful method for posttreatment eradication testing of infection in children.     

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.     

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.     

Prevalence of Helicobacter pylori infection detected by serology and 13C-urea breath test in HIV-1 perinatally infected children

BACKGROUND: Conflicting results have been reported in adults with human immunodeficiency virus (HIV-1) who were investigated for Helicobacter pylori infection. Most studies indicate a lower prevalence than is found in the general population. The purposes of this study were to evaluate H. pylori prevalence by noninvasive methods in a population of children perinatally infected with HIV-1 and to correlate H. pylori prevalence with HIV-1-related clinical and immunologic status. METHODS: H. pylori infection was studied in 45 children perinatally infected with HIV-1 by performing serologic testing of anti-H. pylori immunoglobulin G antibodies and the 13C-urea breath test. RESULTS: Eight children with HIV-1 (17.7%) were positive by serology, and nine (20%) were positive by 13C-urea breath test. No significant differences related to age, previous antibiotic treatment, immunoglobulin administration, antiretroviral treatment, abdominal pain, CD4+ cell count, number of HIV-1 RNA copies, and frequency of severe immunodepression were noted between children with positive 13C-urea breath test results and those with negative results. Children with positive results were significantly more likely to have severe clinical manifestations. CONCLUSIONS: The results show, by both serology and 13C-urea breath test, a prevalence of H. pylori infection comparable with the prevalence in the normal population of the same age. H. pylori prevalence has probably been underestimated in patients with HIV. Results of serologic and histologic analyses for H. pylori require cautious interpretation, especially in severely immunodeficient patients.     

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.     

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.     

Helicobacter pylori infection in Turkish children with gastrointestinal symptoms and evaluation of serology

Helicobacter pylori infection is a common etiopathogenetic factor in children with gastrointestinal symptoms in the developing world. Although serology offers an easy noninvasive method of diagnosis, its sensitivity and specificity are reported to be low among children. In this prospective study, we investigated the frequency and endoscopical and morphological findings of H. pylori infection in 180 Turkish children who underwent upper gastrointestinal endoscopy either for peptic symptoms or on a routine basis and in asymptomatic pediatric patients who underwent endoscopy for other reasons, and then evaluated the diagnostic accuracy of serology in our population. Overall H. pylori infection was diagnosed in 77 of the 180 patients (42.7%) by histology and urease test. The sensitivity of H. pylori specific IgG antibody assay by ELISA was determined to be 100%, while the specificity was 98%, the positive predictive value 97.4%, the negative predictive value 100%. Frequency of H. pylori infection is high in Turkish pediatric patients without gastrointestinal symptoms as well as in children with gastrointestinal complaints. H. pylori specific antibody assay is a noninvasive and sensitive method for the diagnosis of H. pylori infection in the Turkish pediatric population.     

Helicobacter pylori stool antigen test

Objective :Helicobacter pylori (H.pylori) infection is usually acquired in early childhood. Invasive techniques used for diagnosis ofH.pylori infection require endoscopic examination which is expensive and inconvenient and may cause complications. the aim of this study was to evaluate the performance of a new noninvasive diagnostic method, stool antigen test forH.pylori in untreated children with recurrent abdominal pain.Methods: Eighty children (35 female, 45 male) who have undergone upper gastrointestinal endoscopy due to recurrent abdominal pain were included in the study. theH.pylori stool antigen test (HpSA) is based on a sandwich enzyme immunoassay with antigen detection. HpSA sensitivity, specificity, and positive and negative predictive values were determined with reference to the results of both histology and rapid urease test as a gold standard (H. pylori status).Results: While 49 of the 80 children (61%) tested were positive forH.pylori according to the results of both histology and rapid urease test, 28 children had negativeH.pylori status. Among those 49 children, 48 were found to be positive by HpSA. Of 28 patients with negativeH.pylori status, 28 were H.py/ori-negative also in the stool test. the sensitivity, specificity, and positive and negative predictive values of HpSA were found to be 98%, 100%, 100%, and 96.5%, respectively.Conclusion: these findings have demonstrated that HpSA as a relatively simple, inexpensive and time saving noninvasive test is a reliable method for detection ofH.pylori infections in children.     

Efficacy of noninvasive tests in the diagnosis of Helicobacter pylori infection in pediatric patients

BACKGROUND: Helicobacter pylori infection is likely acquired in childhood. Helicobacter pylori is recognized as a cause of gastritis and peptic ulcer. OBJECTIVE: To investigate some noninvasive tests, particularly H pylori fecal antigen, for the diagnosis of H pylori infection in comparison with the gold-standard invasive test, esophagogastroduodenoscopy with biopsy. METHODS: We studied 250 patients (102 male; age range, 3-18 years) who underwent esophagogastroduodenoscopy with biopsy (histologic examination and rapid urease test) for a suspicious upper gastrointestinal disease; in all of them, fecal H pylori antigen, serum H pylori immunoglobulin G, and cytotoxin-associated gene product A immunoglobulin G were measured. Sensitivity and specificity of noninvasive tests were compared with those of the gold-standard esophagogastroduodenoscopy with biopsy. RESULTS: Ninety-three patients (37%) had positive histopathologic (Giemsa staining) and rapid urease test results. The H pylori fecal antigen revealed a sensitivity of 97%, a specificity of 98%, a positive predictive value of 97%, and a negative predictive value of 98%; serum H pylori immunoglobulin G had a sensitivity of 86%, a specificity of 80%, a positive predictive value of 72%, and a negative predictive value of 90%; and serum cytotoxin-associated gene product A immunoglobulin G had a sensitivity of 83%, a specificity of 80%, a positive predictive value of 71%, and a negative predictive value of 89%. CONCLUSIONS: Our study demonstrates that among noninvasive and easily applicable tests, particularly in small children, H pylori fecal test is simple, suitable, and has high accuracy for the screening of H pylori-positive patients.     

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.     

Diagnostic de l’infection à Helicobacter pylori chez l’enfant : quoi de neuf en 2003 ?Helicobacter pylori (H. pylori) infection in childhood: what is new in 2003?

A high prevalence and early colonization of Helicobacter pylori (H. pylori) infection in childhood characterizes the developing countries in contrast to developed ones. Upper gastrointestinal endoscopy including gastric biopsies is the diagnostic gold standard method. Non invasive tests can be used in children, including serology, ¹³C-urea breath test and immunoassay enzyme stool antigen test (HpSA). They present good performance in adults, but less in children under 6 years of age. They can be used for screening, epidemiological studies. Only the ¹³C-urea breath test and the immunoassay enzyme stool antigen test (HpSA) are recommended for the control of eradication. The infection remains often asymptomatic in children and the role of this bacterium in clinical manifestations is the subject of conflicting reports. The treatment of H. pylori infection is influenced by the resistance to the antibiotics used. We suggest that eradication of H. pylori infection should take place only after susceptibility testing since the resistance rate for the metronidazole is of 43% and for the clarithromycine 21% in France. The association of proton pump inhibitor and two antibiotics for 1–2 weeks seems to give the best eradication rates. The crucial question is whether asymptomatic children should be treated to prevent cancer in the future.     

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.     

Diagnostic value of stool antigen and antibody tests for Helicobacter pylori infection in Turkish children with upper gastrointestinal complaints before and after eradication

The aim of this study was to evaluate the diagnostic value of Helicobacter pylori stool antigen (HpSA) and serologic tests before and after eradication therapy for H. pylori in Turkish children in our region with upper gastrointestinal complaints. In this study, 87 children with upper gastrointestinal complaints and 95 children with various symptoms without gastrointestinal complaints were enrolled. H. pylori infection was detected by urea breath test (UBT). HpSA and H. pylori immunoglobulin G (HpIgG) tests were applied to all the children. Eradication treatment was given to the 34 H. pylori-positive children. The UBT was positive in 43 of 87 children (49.4%) with upper gastrointestinal complaints. The sensitivity and specificity of the HpSA in children with upper gastrointestinal complaints were 86% and 84.1%, respectively, and those for the HplgG were 76.7% and 90.9%, respectively. After eradication, the overall HpSA test sensitivity and specificity values were detected as 88.9% and 84%, respectively, and those for the HpIgG were 77.8% and 36%, respectively. The HpSA test is highly sensitive and specific for the diagnosis of H. pylori and for confirming eradication in Turkish children with upper gastrointestinal complaints. However, serology is not a reliable method for the diagnosis of H. pylori infection or for confirming eradication in children.     

Interpreting the 13C-urea breath test among a large population of young children from a developing country.

The 13C-urea breath test is a noninvasive tool for the diagnosis of gastric Helicobacter pylori infection. However, it has not been validated in young children from the developing world, where infection is very common. 13C urea breath tests were performed on 1532 occasions on 247 Gambian infants and children aged from 3 to 48 mo. The means and variances of the separate sub-populations of 13C enrichment results contained within the overall dataset were estimated by a Genstat procedure using the EM algorithm, thereby identifying a cut-off value to discriminate positive from negative results. To illustrate the appropriateness of this calculated cut-off value, 13C urea breath tests were performed upon a small group of 14 patients aged 6 to 28 mo undergoing diagnostic upper endoscopy. Fixed gastric antral biopsies were examined to identify H. pylori. Two subpopulations were identified within the large dataset. A cut-off value of 5.47 delta per thousand relative to Pee Dee Belemnite limestone above baseline at 30 min identified 95% of the normally distributed negative sub-population and 99.4% of the log normal distributed positive sub-population. Comparison with endoscopic data confirmed that this cut-off value was appropriate for this population, as 7/7 children without H. pylori on their gastric biopsies had negative urea breath tests, and 6/7 children with gastric H. pylori colonization had positive urea breath tests. These findings confirm the value of the urea breath test as a diagnostic tool in young children from developing countries. They also offer a way to calculate the most appropriate cut-off value for use in different populations and the likelihood that it will correctly assign any value into the appropriate sub-population, without the need for endoscopy.