Prospective evaluation of a new stool antigen test for the detection of Helicobacter pylori, in comparison with histology, rapid urease test, (13)C-urea breath test, and serology

Background and Aims: This study aimed to evaluate the efficacy of a new polyclonal enzyme immunoassay for the detection of Helicobacter pylori (H. pylori) antigen in stool by determination of the optimal cut‐off value in the screening population. Methods: A consecutive 515 patients undergoing a routine health check‐up were prospectively enrolled. H. pylori infection was defined if at least two of four tests (histology, rapid urease test, ¹³C‐urea breath test, and serology) were positive. A stool antigen test (EZ‐STEP H. pylori) was performed for the detection of H. pylori. The optimal cut‐off value was determined by the receiver–operator characteristic curve. The diagnostic performance of each test was evaluated with regard to the histological diagnosis of atrophic gastritis (AG)/intestinal metaplasia (IM), degree of AG/IM, and old age. Results: Sensitivity, specificity, positive and negative predictive values, and accuracy of the stool antigen test were 93.1%, 94.6%, 95.1%, 92.3%, and 93.8%, respectively. The sensitivity of histology, rapid urease test, and the ¹³C‐urea breath test ranged from 89.1% to 97.6%, and their specificity was > 98%, while serology had high sensitivity, but low specificity. The accuracy of the stool antigen test was comparable to that of other methods (93.6–95.9%), whereas it was higher than that of serology. The stool antigen test still showed good diagnostic performance in the setting of progression of AG/IM and in patients over 40 years. Conclusions: The performance of a new stool antigen test was comparable to that of other methods in the diagnosis of H. pylori infection for the screening population, even with the presence of AG/IM.     

Accuracy of a monoclonal antibody-based stool antigen test in the diagnosis of Helicobacter pylori infection

Background: Recent availability of tests for Helicobacter pylori antigens in stool samples has provided potentially useful tools for epidemiological studies and clinical settings. The aim of this study was to evaluate a monoclonal antibody-based H. pylori antigen stool test in the primary diagnosis of H. pylori infection, and to study the test performance after patients were treated with lanzoprazole, and after eradication therapy. Methods: The study included 122 dyspeptic patients. At gastroscopy, biopsy specimens were obtained for culture and histology. Stool antigen and [[Formula: See Text]C]-urea breath tests were performed concurrently. Positive culture alone or a positive [[Formula: See Text]C]-urea breath test in combination with positive histology defined the reference standard. Forty-three Hp +ve patients were treated with lanzoprazole for 2 to 4 weeks, and stool antigen tests were performed on days 1 and 7 post-treatment. After eradication therapy, 32 patients were re-examined for H. pylori infection. Results: Prevalence of H. pylori was 44.3%. Sensitivity and specificity for the stool antigen test in the primary diagnosis of H. pylori infection were 98% and 94%, with positive and negative likelihood ratios of 16.7 and 0.02, respectively. All patients had positive stool tests immediately after lanzoprazole treatment, whereas 2 patients had negative stool tests after 7 days. Triple therapy rendered all patients stool test negative. Conclusions: The monoclonal antibody-based stool antigen test is an accurate tool in the primary diagnosis of H. pylori infection and after eradication therapy. Lanzoprazole treatment does not influence the clinical performance of the test.     

Comparison of a monoclonal with a polyclonal antibody-based enzyme immunoassay stool test in diagnosing Helicobacter pylori infection after eradication therapy

Background  Recently, a novel Helicobacter pylori stool antigen test (Testmate pylori antigen EIA) using monoclonal antibodies against H. pylori catalase has been developed commercially. This study assessed the diagnostic usefulness of the stool antigen test compared with a polyclonal enzyme immunoassay (HpSA test) after H. pylori eradication. Methods  A total of 150 patients with H. pylori infection were treated by triple therapy with PPI and amoxicillin with either clarithromycin or metronidazole. H. pylori stool antigen was tested 4 and 8 weeks after eradication. The outcome of H. pylori eradication was assessed by urea breath test (UBT) 8 weeks after the end of therapy. Discordant results were followed by endoscopic examination. Results  Of 150 patients enrolled, H. pylori status was negative in 122 cases and positive in 28 cases, assessed by the ¹³C-UBT. On the other hand, the monoclonal stool antigen test results were negative in 126 cases and positive in 24. The polyclonal stool test results were negative in 126 cases and positive in 22. The overall sensitivity and specificity of the monoclonal stool antigen test were 91.6% (95% CI 85.9–97.3%) and 98.4% (95% CI 97.3–99.5%). The overall sensitivity and specificity of the polyclonal stool antigen test were 87.0% (95% CI 86.9–94.0%) and 97.5% (95% CI 96.1–98.9%). Conclusion  The new stool antigen test using monoclonal antibody is useful for the diagnosis of H. pylori eradication 4 weeks after the end of treatment.     

Evaluation of a new immunochromatographic test for Helicobacter pylori IgG antibodies in elderly symptomatic patients

Aim: To determine the diagnostic value of a new serum and whole blood serological IgG antibody test, FlexPack HP, for the diagnosis of Helicobacter pylori in elderly symptomatic patients. Methods: 94 consecutive symptomatic patients who underwent upper endoscopy were studied (mean age, 62.6 years). On endoscopy, the presence of H. pylori infection was examined by biopsies from gastric antrum and body for rapid urease test and histologic examination. Blood was drawn prior to endoscopy and both blood and serum were immediately analyzed for human IgG antibodies to H. pylori by a new commercially available qualitative immunochromatographic method, FlexPack HP. This test incorporates high-molecular weight cell-associated proteins (HM-CAP), which are highly specific for H. pylori IgG antibodies. Results: Overall agreement for FlexPack HP whole blood vs FlexPack HP serum was 100%, and agreement with biopsy results was 71%. The gold standard (detection of H. pylori by histology or urease test) identified H. pylori in 61 patients (65%). Complete agreement was observed between the gold standard test and the serology kit in 72% (68/94) of sera (51 positive and 17 negative). Disagreement was found in sera of 26 patients; 16 sera were negative by the gold standard and positive by FlexPack HP and 10 patients were found negative by serology. The sensitivity of FlexPack HP was 84% and the specificity 52% when compared with the gold standard. Conclusions: FlexPack HP serum and whole blood test is a simple and reliable method for the detection of H. pylori antibodies, with 100% agreement between the serum and blood results. In the elderly symptomatic patients the sensitivity of FlexPack HP was similar to that of other serologic tests, but the specificity was relatively low, limiting its use in this population. (Received Jan. 7, 1998; accepted Aug. 28, 1998)     

A better method for confirming <Emphasis Type="Italic">Helicobacter pylori</Emphasis> infection in Mongolian gerbils

Background. Our aim was to evaluate the accuracy of the stool antigen test and the optimal time point for detecting Helicobacter pylori infection in a Mongolian gerbil model. Methods. We inoculated 8-week-old Mongolian gerbils with H. pylori (Vac A (+)/CagA(+)). The gerbil-infected model was developed as follows: H. pylori was put into broth (about 10⁹ CFU/ml), and 50 gerbils were then fed with 1 ml intragastrically twice within a 3-day interval. Another ten gerbils were fed broth only. Twenty-six weeks after the inoculation, the gerbils were killed. The gastric mucosa was sampled for a series of examinations including culture, histology, rapid urease test, and polymerase chain reaction. Stool samples for a stool antigen test, H. pylori-specific stool antigen assay (HpSA), were collected during weeks 4, 6, 8, 12, and 26 after inoculation. Of the 50 gerbils inoculated with H. pylori, the inoculation was successful in 88%. Severe active gastritis, ulceration, and intestinal metaplasia were obvious. Results. The HpSA test results were sensitivity, 88.6%; specificity, 100%; positive predictive value (PPV), 100%; negative predictive value (NPV), 54.5%, and accuracy, 90%. The HpSA test began to be more sensitive and accurate (P < 0.05) beginning during week 6 after inoculation. We also found that H. pylori could be detected earlier and more easily in the group with high H. pylori density. Conclusions. HpSA seems to be suitable for confirming colonization of gerbils with H. pylori. The optimal testing time point is around 6 weeks after inoculation. This test is a good choice for long-term observation of H. pylori infection in Mongolian gerbils.     

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.     

Accuracy of two plasma antibody tests and faecal antigen test for non-invasive detection of H. pylori in middle-aged Caucasian general population sample

Objective: The aim of the study was to assess the accuracy of two plasma Helicobacter pylori (H. pylori) antibody test-systems and a stool antigen test (SAT) system in a general population sample in Latvia.

Materials and methods: Blood and faecal samples were analysed in healthy individuals (40–64 years), referred for upper gastrointestinal endoscopy according to pilot study protocol within a population-based study investigating gastric cancer prevention strategies (GISTAR pilot study). Antibodies to H. pylori were assessed in plasma by latex-agglutination test and enzyme-linked immunosorbent assay (ELISA). H. pylori antigen in faecal samples was detected by a monoclonal enzyme immunoassay-based SAT. Histological assessment of H. pylori based on a modified Giemsa staining method was used as the gold standard. Individuals having received H. pylori eradication within one year prior to enrolment were excluded. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and overall accuracy were calculated. Receiver-operating characteristic curves were designed to estimate the optimal diagnostic cut-off value of tests.

Results: The analysis included 779 participants for latex-agglutination test, 1002 for ELISA and 672 individual samples for SAT. The sensitivity, specificity, PPV, NPV and overall accuracy were as follows: latex-agglutination test (86;81;87;80;84%), ELISA (97;72;83;94;86%) and SAT (87;81;87;81;85%), respectively. The optimal diagnostic cut-off value for ELISA test was ≥50.26?g/L.

Conclusions: Although the performance of the three tests was comparable to each other, the three test systems showed suboptimal accuracy, with important implications for public health programs based on ‘test-and-treat’ strategy.     

Comparative evaluation of urine-based and other minimally invasive methods for the diagnosis of Helicobacter pylori infection

Background: Diagnostic methods have recently been developed for detecting anti-Helicobacter pylori antibody in urine and H. pylori antigen in stool samples. Our aim was to evaluate the usefulness of noninvasive urine-based methods for the diagnosis of H. pylori infection. Methods: The study subjects were 100 asymptomatic Japanese volunteers. We investigated the diagnostic efficacy of various noninvasive diagnostic methods; five serological tests (Immunis anti-pylori, HM-CAP, EIAgen Helicobacter pylori IgG, Helico G, and GAP-IgG), one test for antigen in stool (HpSA enzyme immunoassay [EIA]), and two tests for antibody in urine (Urinelisa and Rapirun) by using the urea breath test (UBT) as the gold standard. Results: Fifty subjects were diagnosed as positive for H. pylori infection by the UBT. The serological tests showed good sensitivity, specificity, and accuracy. The diagnostic values of the feces-based test (HpSA EIA) were lower than that of the serological tests. The sensitivities of the two urine-based methods in frozen urine samples were markedly lower than those of the other tests. However, the use of unfrozen samples markedly improved the diagnostic accuracy of these urine-based tests, which was then superior to that of the feces-based method. Conclusions: This study clearly showed that urine-based tests were useful for the diagnosis of H. pylori infection. However, the use of frozen urine samples was not appropriate for the detection of anti-H. pylori antibody. Received: November 5, 2001 / Accepted: February 22, 2002 Acknowledgments. We wish to thank Ms. Rika Tohma, Ms. Shiho Yamamoto, Ms. Yukiko Inoue, Mr. Masahiro Ishibashi, and Mr. Nobuo Sasaki for their technical supports. This work was supported in part by Grants-in-Aid for Scientific Research from the Ministry of Education, Science, and Culture of Japan. Reprint requests to: K. Adachi     

Stool antigen tests for the management of Helicobacter pylori infection

Stool antigen tests(SATs)are noninvasive diagnostic modules for Helicobacter pylori(H.pylori)infection.Two types of SATs exist for the diagnosis of H.pylori infection,one based on enzyme immunoassay(EIA)and another on immunochromatography(ICA).SATs do not require expensive chemical agents or specified equipment;hence,they are less expensive compared with the urea breath test.Both European and Japanese guidelines have shown that EIA-based SATs using monoclonal antibodies are useful for primary diagnosis as well as for the assessment of eradication therapy.ICA-based tests do not require particular equipment and are therefore useful in developing countries.SATs are also useful for the diagnosis of H.pylori infection in children and post gastric surgery patients.SATs performed via EIA can assess H.pylori infection in a large number of subjects,almost as well as serology.Thus,SATs would be useful or detecting current infection in such a survey to identify and eradicate H.pylori infection.The accuracy of SATs is lower when the stool samples are unformed or watery,because H.pylorispecific antigens in the stool samples are diluted.Temperature and the interval between stool sample collection and measurement also affect the results of SATs.The choice of test kit depends on the sensitivity and specificity in each region and the circumstances of each patient.     

Evaluation of the monoclonal stool antigen test for Helicobacter pylori in an Asian population with dyspepsia

OBJECTIVE: Although well established in the West, stool antigen tests (SAT) are not widely used in Asia. Data on the accuracy of this test in Asia is sparse and, to date, there have been no studies looking at the more refined monoclonal SAT. The aim of this study is to validate the diagnostic accuracy of a stool antigen test, Hp STAR, for the detection of Helicobacter pylori. METHODS: Consecutive new patients with dyspepsia, referred to the endoscopy unit were recruited. At endoscopy, biopsies were taken for rapid urease tests and histology. Stool specimens were collected before any therapy was given and were tested for H. pylori using the monoclonal SAT HpSTAR test. Samples were collected from 90 patients. The stool antigen results were compared with the results of rapid urease tests and histopathology, which were used together as the gold standard test in the diagnosis of H. pylori. RESULTS: Of the 90 patients tested, 45 were H. pylori positive and 45 were H. pylori negative. There was one false positive and one false negative test. The sensitivity, specificity, positive predictive value and negative predictive value for the Hp STAR were identical: 97.8% with a 95% confidence interval of 88.2-99.9%. The diagnostic accuracy was 97.8% with a 95% confidence interval of 92.2-99.7%. CONCLUSION: The monoclonal stool antigen test, HpSTAR is a highly accurate test for the diagnosis of H. pylori.     

Evaluation of two stool antigen tests for the detection of Helicobacter pylori infection in the Chinese population

BACKGROUND AND AIM: The stool antigen test, the HpSA test, has been validated mainly in Western countries, but not properly in the Chinese population. Recently, another stool antigen test, the Apollo test, was developed, but its accuracy has rarely been validated. The aim of this study is to compare the accuracy of these two tests in the diagnosis of Helicobacter pylori infection in the Chinese population. METHODS: Consecutive dyspeptic patients referred for upper endoscopy were recruited. During endoscopy, biopsies were taken for the rapid urease test and histological examination as the gold standard. Stool specimens were collected and used for the HpSA and Apollo tests. RESULTS: Overall, 86 patients (39 males and 47 females, with a mean age of 55.8 years) were recruited. Helicobacter pylori infection was present in 44 (51%) patients as determined by the gold standard. The sensitivity, specificity and accuracy were 86.4, 100, and 93.0%, respectively, for the HpSA, and 90.9, 97.6, and 94.2%, respectively, for the Apollo test when cases with equivocal results were considered as positive. In addition, agreement was achieved in 81 (94.2%) cases between the two tests, with a Kappa value of 0.887. CONCLUSION: Both the HpSA and Apollo tests achieve acceptable sensitivity and excellent specificity, with accuracies of over 90% for the detection of H. pylori infection in the Chinese population.     

Prospective,study comparing the accuracy of two different stool antigen tests (Premier Platinum HpSA and novel ImmunoCard STAT! rapid test) for the diagnosis of Helicobacter pylori infection

BackgroundAt present only monoclonal EIA (enzyme-immunoassay) stool antigen-tests have obtained optimal accuracy in the diagnosis of Helicobacter pylori. Our aim was to evaluate the accuracy of two stool antigen-tests, the validated Premier Platinum HpSA PLUS (EIA test) and the newly available ImmunoCard STAT! HpSA HD (rapid test) for the initial diagnosis and the confirmation of eradication of H. pylori infection.Patients and methodsPatients with indication of H. pylori diagnosis, or confirmation after treatment were included. Data were coded to protect personal data and ensure blindness between tests. Accuracy was considered as coincident diagnosis with the gold standard (¹³C-urea breath test, UBT). The EIA was used as a bench standard. All stool tests were performed in duplicate.Results264 patients completed the protocol (100 naïve, 164 post-eradication). Average age was 52 years, 61% women, 11% ulcer. Positive diagnoses by UBT were 41% for naïve and 17% for post-eradication. Overall ImmunoCard and EIA accuracies were respectively 91% (95%C.I. = 88–94%) and 89% (86–93%), sensitivities 72% (67–78%) and 72% (67–78%), and specificities 98% (96–100%), and 95% (92–97%). Concordance between ImmunoCard and EIA was 95% (93–98%).DiscussionOur results indicate that the newly available ImmunoCard rapid stool antigen-test achieves 90% accuracy, with high specificity but suboptimal sensitivity. The ImmunoCard attained equivalent accuracies as the EIA bench standard, with 95% concordance.     

Comparison of invasive methods and two different stool antigen tests for diagnosis of H pylori infection in patients with gastric bleeding

AIM: To compare two different H pylori stool antigen tests as noninvasive diagnostic methods. METHODS: The study population consisted of 22 upper gastrointestinal system bleeding patients. Urea breath test (UBT), rapid urease test (RUT) and histopathological examination were applied to all patients. Stool specimens from these patients were examined by rapid STRIP!HpSA and one step simple H pylori antigen cassette test for the detection of H pylori antigens. RESULTS: For these 22 patients, 15 (68.2%) were diagnosed as positive and seven (31.8%) were diagnosed negative for H pylori infection by the gold standard methods. Whereas 10 (45.5%) were positive and 12 (54.5%) were diagnosed negative by the rapid STRiP!HpSA test. The sensitivity, specificity, positive and negative predictive values were 60%, 86%, 90% and 50%, respectively. When compared to the gold standard methods, these differences were not significant. However, six patients (27.3%) were positive, and 16 (72.7%) were negative by the simple H pylori stool antigen cassette test. The sensitivity, specificity, positive and negative predictive values were 33%, 86%, 83% and 38%, respectively. Compared to the gold standard methods, the simple H pylori stool antigen cassette test results were significantly different (P = 0.012). CONCLUSION: Rapid STRIP! HpSA test could be used as a routine diagnostic tool in the microbiology laboratory for assessing clinical significance and eradication control of H pylori in upper gastrointestinal system bleeding patients.     

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     

Evaluation of the Stool Antigen Test for <Emphasis Type="Italic">Helicobacter pylori</Emphasis> in Children and Adolescents

The stool antigen test for Helicobacter pylori is a noninvasive immunoassay to diagnose active infection with Helicobacter pylori in human fecal samples. Its performance in children and teenagers has been tested in some developed countries, showing a sensitivity and specificity above 90%, however, its accuracy in developing countries and in children under 6 years is not well established. To determine the accuracy of the test for diagnosing Helicobacter pylori infection in children and teenagers, we evaluated 133 patients (4 months to 17 years old). The gold standard was a positive culture or positive histology and rapid urease test. The test was done according to the manufacturers instructions. However, modifications were introduced for better reproducibility. Samples were analyzed twice and results are expressed as optical density (OD) determined spectrophotometrically at 450 nm. HpSA was considered positive at OD 0.160 and negative at OD < 0.140. One hundred twenty-seven of the 133 (95.5%) patients were included. There were no infected infants. The test showed a 94.6% sensitivity (95% CI: 90.6–98.5) and a 96.5% specificity (95% CI: 93.3–99.7). At ages 2 to 6 years the specificity was 96.4% (95% CI: 85.1–99.2) and the sensitivity was 80.0% (95% CI: 64.8–89.7), at ages 6 to 10 years the sensitivity was 100.0% and the specificity 95.7%, and above 10 years the sensitivity and specificity were 100.0%. We conclude that the test is efficient in adolescents and children, however there is a need for further studies with a greater number of patients for evaluation of its accuracy in infants.     

Utility and limitations of a method for detecting Helicobacter pylori-specific antigens in the stool

Background: Recently, a method for detecting Helicobacter pylori-specific antigens in the stool (HpSA) has been proposed to be useful clinically. The aim of this study was to determine the accuracy of HpSA for the diagnosis of H. pylori infection, including early assessment after eradication treatment, and the potential for quantitative evaluation of H. pylori in the stomach. Methods: The subjects were 85 patients with gastroduodenal disorders who underwent endoscopic examination. Of these, 36 were treated for eradication of H. pylori infection and reassessed 4–8 weeks after treatment. HpSA was tested by enzyme immunoassay. For the definitive diagnosis of H. pylori infection, biopsy specimens were taken endoscopically and examined by quantitative culture, rapid urease test, and immunohistostaining. In addition, serum antibody against H. pylori was tested before the eradication treatment and a ¹³C-urea breath test was conducted after treatment. The results of these reference tests were compared with those obtained by HpSA. Results: The sensitivity and specificity of HpSA were 90.4% and 100% before eradication treatment and 57.1% and 100% after the treatment. There was a positive correlation between the optical density of HpSA and the number of H. pylori bacilli evaluated by quantitative culture. Conclusions: The HpSA test is considered to be an accurate method for the diagnosis of H. pylori infection, with high specificity. However, there may be problems of false negativity if HpSA is used for the early assessment of treatment efficacy. Furthermore, HpSA is suggested to have potential for the quantitative evaluation of H. pylori status in the stomach. Received: March 29, 2002 / Accepted: August 30, 2002 Reprint requests to: Y. Noda, Present address: Department of Internal Medicine, Toyama Prefectural Central Hospital, 2-2-78 Nishinagae, Toyama 930-8550, Japan     

ACCURACY OF ENDOSCOPIC DIAGNOSIS OF HELICOBACTER PYLORI IN PATIENTS WITH HEMORRHAGIC PEPTIC ULCERS

Background: Recent progress in Helicobacter pylori eradication has resulted in dramatic improvements in the incidence of peptic ulcers and decreased rates of ulcer relapse. Because bleeding is an important complication of ulcer diseases, accurate diagnosis of H. pylori infection is necessary. Methods: We studied the efficacy of diagnostic methods to detect H. pylori in hemorrhagic peptic ulcer patients. A total of 59 patients who had received emergency endoscopy because of symptoms such as hematemesis, melena or tarry stool, were examined. Endoscopic methods of H. pylori diagnosis (culture, histological assessment and rapid urease test) and serum anti‐H. pylori assays were used in the hemorrhagic peptic ulcer group and the control group. Results: The percentage of endoscopically determined H. pylori‐negative patients was significantly higher in the hemorrhagic ulcer group than the control group (P < 0.05). Out of the endoscopically determined H. pylori‐negative patients in the hemorrhagic ulcer group, 78.9% were serologically H. pylori‐positive. Conclusion: Endoscopic methods are not sufficient for the diagnosis of H. pylori infection in hemorrhagic ulcer patients. Therefore, serum anti‐H. pylori assessment should also be performed for such patients.     

Diagnosis of Helicobacter pylori infection: Current options and developments

Accurate diagnosis of Helicobacter pylori (H. pylori) infection is a crucial part in the effective management of many gastroduodenal diseases. Several invasive and non-invasive diagnostic tests are available for the detection of H. pylori and each test has its usefulness and limitations in different clinical situations. Although none can be considered as a single gold standard in clinical practice, several techniques have been developed to give the more reliable results. Invasive tests are performed via endoscopic biopsy specimens and these tests include histology, culture, rapid urease test as well as molecular methods. Developments of endoscopic equipment also contribute to the real-time diagnosis of H. pylori during endoscopy. Urea breathing test and stool antigen test are most widely used non-invasive tests, whereas serology is useful in screening and epidemiological studies. Molecular methods have been used in variable specimens other than gastric mucosa. More than detection of H. pylori infection, several tests are introduced into the evaluation of virulence factors and antibiotic sensitivity of H. pylori, as well as screening precancerous lesions and gastric cancer. The aim of this article is to review the current options and novel developments of diagnostic tests and their applications in different clinical conditions or for specific purposes.     

Helicobacter pylori infection - recent developments in diagnosis

Considering the recommended indications for Helicobacter pylori (H. pylori) eradication therapy and the broad spectrum of available diagnostic methods, a reliable diagnosis is mandatory both before and after eradication therapy. Only highly accurate tests should be used in clinical practice, and the sensitivity and specificity of an adequate test should exceed 90%. The choice of tests should take into account clinical circumstances, the likelihood ratio of positive and negative tests, the cost-effectiveness of the testing strategy and the availability of the tests. This review concerns some of the most recent developments in diagnostic methods of H. pylori infection, namely the contribution of novel endoscopic evaluation methodologies for the diagnosis of H. pylori infection, such as magnifying endoscopy techniques and chromoendoscopy. In addition, the diagnostic contribution of histology and the urea breath test was explored recently in specific clinical settings and patient groups. Recent studies recommend enhancing the number of biopsy fragments for the rapid urease test. Bacterial culture from the gastric biopsy is the gold standard technique, and is recommended for antibiotic susceptibility test. Serology is used for initial screening and the stool antigen test is particularly used when the urea breath test is not available, while molecular methods have gained attention mostly for detecting antibiotic resistance.     

Secretion of Gastric Inhibitory Polypeptide in Patients with Bile Duct Obstruction

Background: The usefulness of the rapid urease test (RUT) in diagnosing Helicobacter pylori infection after peptic ulcer surgery is unknown. Methods: Patients who had undergone peptic ulcer surgery were offered endoscopic examination if they presented with dyspepsia or gastrointestinal bleeding. Biopsy specimens were taken for RUT and histology from the corpus and the stoma in patients who had undergone partial gastrectomy or from the corpus and the antrum in patients who had undergone vagotomy. Histologic examination using haematoxylin and eosin stain and Warthin-Starry stain were used as the gold standard. Results: Ninety patients were studied (69 had partial gastrectomy and 21 had vagotomy). Forty-three patients (32 in the partial gastrectomy group and 11 in the vagotomy group) were positive for H. pylori by histology. The respective sensitivity of RUT was 59% (stoma) and 75% (corpus) in the partial gastrectomy group (P = 0.36) and 55% (antrum) and 73% (corpus) in the vagotomy group (P = 0.51). Conclusions: RUT is not sensitive for detecting H. pylori after acid reduction surgery.