Accuracy of an enzyme immunoassay for the detection of Helicobacter pylori in stool specimens in the diagnosis of infection and posttreatment check-up

OBJECTIVE: The aim of this study was to assess the reliability of a newly developed enzyme immunoassay for Helicobacter pylori-specific antigen detection in stools (HpSA) compared to other standardized diagnostic techniques such as histology (H), rapid urease test (RUT) and 13C-urea breath test (UBT) to diagnose H. pylori infection and to evaluate its usefulness in determining H. pylori status after treatment. METHODS: One hundred eighty-eight patients referred to our department for upper gastrointestinal endoscopy were included. H. pylori infection was confirmed in all patients by HpSA test in stools, RUT, UBT, and H. Patients were defined as positive for H. pylori if RUT and UBT or H were positive. A total of 142 symptomatic patients received eradication treatment and were reassessed 6 wk after therapy; for 70 of these patients, stool samples were also collected at 24 h and 6 months after finishing eradication treatment. In the posttreatment follow-up, UBT was used as gold standard. RESULTS: The sensitivity of HpSA test for the diagnosis of H. pylori infection using a cut-off value of 0.130 was 89.5% and its specificity 77.8%. This specificity was lower than that obtained with UBT, H, and RUT. In the early follow-up the sensitivity of HpSA test was null. At 6 weeks and at 6 months post-treatment its sensitivity was 70.4% and 50% and its specificity was 81.6% and 79.3%, respectively. CONCLUSIONS: The HpSA stool test, using a cut-off value of 0.130, may be useful for the primary diagnosis of H. pylori infection, with sensitivity similar to that obtained with other standard tests, but with less specificity. HpSA test is not useful for early monitoring of treatment efficacy. At 6 wk and at 6 months posttreatment, HpSA test lacks accuracy as compared to UBT for evaluating the outcome of the eradication treatment.     

Immunological rapid urease test using monoclonal antibody for Helicobacter pylori

BACKGROUND AND AIM: The current diagnostic methods for detecting Helicobacter pylori infection include rapid urease test (RUT), urea breath test (UBT), histology, culture, and serum antibody detection. The present study evaluated the efficacy of a novel highly specific test, an immunological RUT (IRUT), that uses a monoclonal antibody against H. pylori urease. METHODS: The clinical evaluation of the IRUT was performed in 100 subjects. Each gastric mucus sample obtained during endoscopic examination was incubated for 15 min with a solid tip coated with monoclonal antibody for H. pylori urease, and then the tip was introduced into a pH-monitoring cell containing urea solution. The change in pH of the solution after the enzymatic reaction (delta pH) was measured. The performance of the IRUT was compared with culture, histology, RUT, and UBT. RESULTS: Of the 47 H. pylori-positive subjects, 43 were IRUT positive (sensitivity, 91.5%), and of the 53 H. pylori-negative subjects, 52 were negative (specificity, 98.1%). Compared with the usual diagnostic methods, IRUT had high sensitivity and specificity for the detection of H. pylori and was no less efficient. CONCLUSIONS: IRUT is a sensitive, specific and very rapid (within 20 min) method of detecting H. pylori infection.     

Polymerase chain reaction： A sensitive method for detecting Helicobacterpyloriinfection in bleeding peptic ulcers

AIM: To assess the sensitivity and specificity of polymerase chain reaction (PCR) in detecting Helicobacter pylori(H pylon) infection in patients with bleeding peptic ulcers, and to compare its diagnostic efficacy with other invasive and non-invasive tests. METHODS: From April to September 2002, H pylori status in 60 patients who consecutively presented with gastroduodenal ulcer bleeding was examined by rapid urease tests (RUT), histology, culture, PCR, serology and urea breath tests (UBT). RESULTS: The sensitivity of PCR was significantly higher than that of RUT, histology and culture (91% vs 66%, 43% and 37%, respectively; P = 0.01, <0.001, <0.001, respectively), but similar to that of serology (94%) and UBT (94%). Additionally, PCR exhibited a greater specificity than serology (100% vs 65%, P<0.01). However, the specificity of PCR did not differ from that of other tests. Further analysis revealed significant differences in the sensitivities of RUT, culture, histology and PCR between the patients with and those without blood in the stomach (P<0.01, P= 0.09, P<0.05, and P<0.05, respectively). CONCLUSION: PCR is the most accurate method among the biopsy-based tests to detect H pylori infection in patients with bleeding peptic ulcers. Blood may reduce the sensitivities of all biopsy-based tests.     

Capsule 13C-urea breath test for the diagnosis of Helicobacter pylori infection

AIM: To compare the accuracy of capsule 13C-urea breath test (UBT) with conventional invasive methods for the diagnosis of Helicobacter pylori infection. METHODS: One hundred patients received CLO test, histological examination, culture and 100- or 50-mg capsule UBT for the diagnosis of H pylori infection. H pylori infection was defined as those with positive culture or positive results from both histology and CLO test. RESULTS: Both the sensitivity and specificity of the 100-mg capsule UBT (n=50) were 100%. The sensitivity and specificity of the 50-mg capsule UBT (n = 50) were 96.4 and 100%, respectively. Taken together, the accuracy of capsule UBT (n =100) was higher than that of CLO test, histology and culture (100% vs 92%, 91% and 89%, respectively; P= 0.035, 0.018 and 0.005, respectively). Our data showed that the optimal timing of sampling for 100-and 50-mg capsule UBT was 15-30 and 6-15 min, respectively. CONCLUSION: Capsule UBT has a higher accuracy compared with biopsy-based tests. It is an ideal method for the diagnosis of H pylori infection.     

幽门螺杆菌粪便抗原试验的多中心研究

目的：评估幽门螺杆菌（H.pylori)粪便抗原（HpSA)试验诊断H.pylori感染的准确性。方法：应用酶免疫反应原理进行HpSA试验，在大样本、多中心研究中进行HpSA试验的评估。995例因消化不良症状接受胃镜检查者纳入本研究，所有患者均以HpSA试验、快速尿素酶试验（RUT）和组织学（或培养）方法检测H.pylori。以RUT和组织学（或培养）联合检测作为“金标准”，两项试验均阳性者定为H.pylori感染。结果：以光密度值≥0.16为阳性，HpSA检测诊断H.pylori感染的敏感性为93.5%(478/511)，特异性为94.2%(456/484)，阳性预测值为94.5%(478/506)，阴性预测值为93.3%(456/489)，总的检测准确性为93.9%(934/995)。结论：HpSA试验是一种简便、准确的非侵入性H.pylori感染检测方法。     

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

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

红外能谱仪检测~(13)C-尿素呼气试验诊断幽门螺杆菌感染

目的：验证红外能谱仪检测１３Ｃ－尿素呼气试验（ＵＢＴ）诊断幽门螺杆菌（Ｈ．ｐｙｌｏｒｉ）感染的可靠性,并与气体质谱仪检测结果作一比较。方法：对７６例患者以红外能谱仪进行１３Ｃ－ＵＢＴ检测Ｈ． ｐｙｌｏｒｉ感染,Ｈ． ｐｙｌｏｒｉ感染状态由快速尿素酶试验、组织学检查以及细菌培养确定。其中１７例患者的呼气样本分别用红外能谱仪与气体质谱仪进行检测。结果：７６例患者中Ｈ． ｐｙｌｏｒｉ阳性者４３例（５６．６％）,红外能谱仪进行１３Ｃ－ＵＢＴ的测定结果为４１例（５３．９％）,其敏感性和特异性分别达到９３．０％和９７．０％。气体质谱仪与红外能谱仪的检测数值相差无几。结论：以红外能谱仪进行１３Ｃ－ＵＢＴ检测可靠、准确地诊断Ｈ．ｐｙｌｏｒｉ感染,并具有简单、实用的特点。红外能谱仪与气体质谱仪一样可被广泛应用于Ｈ．ｐｙｌｏｒｉ检测。     

13C urea breath test for (Helicobacter pylori): determination of the optimal cut-off point in a Canadian community population.

AIM: To determine the test characteristics and the optimal cut-off point for the (13)C urea breath test ((13)C UBT) in a Canadian community laboratory setting. METHODS: Of 2232 patients (mean age +/- SD: 51+/-21 years, 56% female) who completed a (13)C UBT, 1209 were tested to evaluate the primary diagnosis of (Helicobacter pylori) infection and 1023 were tested for confirmation of eradication following treatment. Cluster analysis was performed on the (13)C UBT data to determine the optimal cut-off point and the risk of false-positive and false-negative results. Additionally, 176 patients underwent endoscopic biopsy to allow validation of the sensitivity and specificity of the (13)C UBT against histology and microbiology using the calculated cut-off point. RESULTS: The calculated cut-off points were 3.09 delta/1000 for the whole study population (n=2232), 3.09 delta/1000 for the diagnosis group (n=1209) and 2.88 delta/1000 for the post-treatment group (n=1023). When replacing the calculated cut-off points by a practical cut-off point of 3.0 delta/1000, the risk of false-positive and false-negative results was lower than 2.3%. The (13)C UBT showed 100% sensitivity and 98.5% specificity compared with histology and microbiology (n=176) for the diagnosis of active (H pylori) infection. CONCLUSIONS: The (13)C UBT is an accurate, noninvasive test for the diagnosis of (H pylori) infection and for confirmation of cure after eradication therapy. The present study confirms the validity of a cut-off point of 3.0 delta/1000 for the (13)C UBT when used in a large Canadian community population according to a standard protocol.     

Evaluation of a new enzyme immunoassay for detecting Helicobacter pylori in feces: a prospective pilot study

OBJECTIVE: There is an increasing interest in noninvasive tests for detecting Helicobacter pylori (H. pylori) infection. Unlike serological and urea breath tests, the possibility of searching for H. pylori in feces has been scarcely investigated. The aim of this prospective pilot study was to evaluate the usefulness of a new enzyme immunoassay for detecting H. pylori antigens in feces, as a predictor of H. pylori status in the pre- and posttreatment settings. METHODS: One hundred and fifty-four symptomatic, anti-H. pylori untreated patients (Group A) and 116 anti-H. pylori treated patients (Group B) underwent gastroscopy with biopsies of the antrum and corpus for histology (H) and rapid urease test (RUT). In the anti-H. pylori treated group, a 13C-urea breath test (UBT) was also performed. In Group A, H. pylori status was defined as positive or negative when both H and RUT gave concordant positive or negative results. In Group B, the patients were considered eradicated if all three tests were negative. A stool specimen was collected from all patients the day after gastroscopy, and tested by using an enzyme immunoassay commercial kit for detecting H. pylori antigens in feces (HpSAT). RESULTS: Eighty-five patients in Group A (55%) and 44 in Group B (38%) were H. pylori infected. On the whole, HpSAT showed a sensitivity of 94% and specificity of 86%. In Group A and Group B, sensitivity and specificity were 94% versus 93%, and 90% versus 82%, respectively (p < 0.05). CONCLUSIONS: HpSAT seems to be a reliable method for predicting H. pylori status in anti-H. pylori untreated patients. Conversely, the test appears less suitable to evaluate the outcome of the eradicating treatment. Consequently, it is likely to be accepted for the primary diagnosis of H. pylori status, particularly in dyspeptic young patients.     

~(13)C-尿素呼气试验诊断幽门螺杆菌感染的研究

本研究旨在评估~(13)C,尿素呼气试验检测幽门螺杆菌感染的可靠性。方法:我们在82例因胃病而行胃镜检查的患者胃窦和胃体取多个活检标本,作组织学、牯膜涂片和快速尿素酶试验,以决定是否感染幽门螺杆菌,并作~(13)C-尿素呼气试验。~(13)C-尿素呼气试验的敏感性、特异性、阳性预测值、阴性预测值是与组织学和尿素酶方法检测幽门螺杆菌的结果比较而计算得到。结果:~(13)C-尿素呼气试验的敏感性97.92％,特异性100％,阳性预测值100％,阴性预测值97.14％,准确性98.78％。结论:~(13)C-尿素呼气试验有高度敏感性和特异性,对确定患者的幽门螺杆菌感染状态是一可靠的无创伤的诊断方法。     

14C]-urea breath test to confirm eradication of Helicobacter pylori

BACKGROUND: Treatment for Helicobacter pylori reduces ulcer recurrence. Eradication rates of the organism vary with different drug regimens from 30% to 90%. There is a need to identify patients who have failed treatment. [14C]-Urea breath test (UBT) is non-invasive, sensitive, safe and highly reliable test for diagnosis of H. pylori infection. As there is a paucity of reports on the utility of [14C]-UBT in confirming H. pylori eradication, this study was undertaken. METHODS: Thirty-eight patients (age 34 +/- 17 years, range 16-84 years, 27 men) with upper gastrointestinal symptoms underwent upper gastrointestinal endoscopy. Baseline H. pylori infection was diagnosed by identification of the organism on antral biopsies and positive rapid urease test (RUT). After 1 month of completion of treatment, repeat RUT and histological examination of antral endoscopic biopsies were performed. Eradication of H. pylori was defined as absence of the organism on histology, and negative RUT. The [14C]-UBT was performed using 185 kBq [14C]-urea dissolved in 300 mL water. Breath samples were collected once before ingestion of [14C]-urea, and subsequently at 5 and 15 min. Results were expressed as 14CO2/mmol CO2 exhaled as per cent of administered urea. RESULTS: Endoscopy revealed antral gastritis (n = 14), duodenal ulcer (n = 8), duodenitis (n = 2), oesophagitis (n = 1), antral gastritis and duodenal ulcer (n = 3), antral gastritis and duodenitis (n = 7) and normal upper gastrointestinal endoscopy (n = 3). All the 20 patients who were negative for H. pylori on RUT and histology, tested negative for H. pylori on [14C]-UBT. However, of 18 patients shown to have H. pylori infection on RUT and histology, 16 were positive for H. pylori on [14C]-UBT. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of [14C]-UBT were 100, 89, 91, 100 and 95% respectively. CONCLUSIONS: The [14C]-UBT is a reliable indicator of H. pylori eradication after treatment. It can obviate the need for antral biopsies to confirm eradication of H. pylori after completion of treatment.     

四种检测幽门螺杆菌感染方法的评价──病理组织学、血清学、~(13)C呼气试验和快速尿素酶试验

目的检测幽门螺杆菌（HelicobacterpyloriHp）的方法很多，本文对病理组织学，血清学，快速尿素酶和13C呼气试验进行分析评价．方法对70例有消化道症状的患者进行以上四种方法检测幽门螺杆菌，其中二项阳性者认为有Hp感染。结果病理组织学，血清学，13C呼气试验，快速尿素酶检测的敏感性分别为83．33％，90．74％，96．30％，85．52％；特异性分别为100％，100％，81．25％，75％。四种方法的阳性预测值分别为11％，100％，94．55％，92％；阴性预测值分别为64％，76．19％，86.67％，60％。结论病理组织学与呼气试验是检测Hp感染的较准确的测定方法，呼气试验更能反映“全胃”Hp感染状况，目前可作为抗Hp药物疗效监测的“金标准”。血清学检测和快速尿素酶法操作方便，费用低，是临床常用的检测手段。     

Helicobacter pylori infection diagnosis in hospitalised elderly patients: the stool antigen test (HpSA) in comparison with other methods

BACKGROUND AND AIMS: Helicobacter pylori (Hp) infection prevalence increases with age. In elderly patients, who often do not collaborate and who are affected by multiple pathologies, worldwide-recognised invasive and non-invasive methods (histology and Urea Breath Test) are not easy to apply. A new test based on the detection of Hp antigens in the stool (HpSA test) is now available. The aim of our study was to evaluate the sensitivity and specificity of the HpSA test, and the interference of drugs (acid suppression, antibiotics) on test performance. METHODS: Hp infection was detected by UBT, HpSA and histology in 122 hospitalised elderly subjects, divided into two groups according to therapy in the last month. Subjects were classified as being Hp-positive if two test results (histology and UBT) were positive, and Hp-negative if the same two test results were negative. RESULTS: The sensitivity and specificity of the HpSA test compared with two tests (histology and UBT) were respectively 76 and 95%. In the group of patients who had not received drugs, the sensitivity and specificity of the HpSA test were respectively 76 and 96%. Instead, in the group of patients who had received pharmacological therapy, sensitivity and specificity values were respectively 67 and 100%. HpSA-positive patients had received acid suppression for 9.2 +/- 8.9 days, and false-negative patients for 27.2 +/- 9.9 days. CONCLUSIONS: The HpSA test is simple, inexpensive, and non-invasive for Hp detection, especially in elderly subjects with no compliance. It is influenced only after several days by therapy common in the elderly.     

Evaluation of urine ELISA test for detecting Helicobacter pylori infection in Taiwan： A prospective study

AIM: To evaluate the diagnostic accuracy and clinical utility of a new ELISA (URINELISA) test for detecting Helicobacter pylori(H pylori) antibody in the urine of Taiwanese population. METHODS: In this prospective study, 317 consecutive dyspeptic patients (171 men, 146 women; mean age, 51.0 years) were included. They underwent gastroendoscopy for evaluation. Invasive tests, including culture, histology, and rapid urease test (RUT), and non-invasive ~(13)C-urea breath test were preformed. At the same time, urine specimens were collected for URINELISA. The status of H pylori infection was considered as positive when either culture was positive, or when two of the other, RUT, histology or 13C-UBT, were positive. RESULTS: The sensitivity, specificity, positive predictive value, and negative predictive value of URINELISA are 91.7% (211/230), 90.8% (79/87), 96.3% (211/219), and 80.6% (79/98) respectively. CONCLUSION: This URINELISA test is reliable, inexpensive and easy-to-use. The high diagnostic accuracy warrants the use of URINELISA as a first-line screening tool for diagnosis of H pylori infection in untreated patients.     

14C-urea breath test for assessment of gastric Helicobacter pylori colonization and eradication.

BACKGROUND AND OBJECTIVE: Urea breath test (UBT) is a reliable noninvasive technique for detecting gastric Helicobacter pylori colonization. 14C isotope-based test requires simple equipment and is inexpensive. We studied the utility of 14C-UBT in diagnosis of gastric H. pylori infection. METHODS: Presence of H. pylori was studied using antral histology and culture in patients with rapid urease test (RUT)-positive peptic ulcer. 14C-UBT was performed using a 185-kBq dose. Radioactivity in 15-min breath samples was measured using a beta-scintillation counter and result expressed as % dose recovered/mmol CO2. H. pylori was considered positive when any two tests were positive. All tests were repeated one month after completion of H. pylori eradication therapy. RESULTS: Among 41 patients (duodenal ulcer 36, gastric ulcer 5), H. pylori was detected by histology in 23 (56%) and by culture in 27 (66%). Overall, H. pylori was detected in 28 (68%) patients. Follow-up assessment was possible in 28 patients: 26 cleared the infection (all three tests negative). Mean 14C recovery values at 15 minutes associated with H. pylori-positive status were significantly higher (12.3 [SD 6.8] x 10(-3); n=30; p<0.001) than those associated with H. pylori-negative status (2.1 [0.9] x 10(-3); n=26). Using receiver-operating-characteristic analysis of 15-minute 14C recovery values, a cut-off of 6.5x10(-3) gave the best separation of H. pylori-positive and -negative cases. 14C-UBT had 93% sensitivity, 96% specificity and 95% accuracy. CONCLUSION: 14C-UBT appears to be a reliable noninvasive test for diagnosis of H. pylori infection.     

Evaluation of endoscopy-based diagnostic methods for the detection of Helicobacter pylori.

BACKGROUND: Helicobacter pylori is an etiological factor in duodenal ulcer. Few studies have objectively assessed the accuracy of diagnostic methods for the detection of H. pylori. METHODS: The sensitivity and specificity of histology, touch smear, rapid urease test (RUT) and brush cytology of endoscopic antral biopsy from patients with duodenal ulcer were compared. Forty-nine patients were evaluated before, and 34 after, eradication therapy. Each time, sampling was done for all 4 tests. The infection status for each sample was established by a positive concordance of results of three of four tests. RESULTS: The highest degree of agreement was between RUT and cytology (kappa = 0.69). Brush cytology (100%) followed by RUT (94.5%) were the most sensitive tests. Histology had the highest specificity (89.3%). A combination of RUT or brush cytology with histology had the maximum chance of detecting H. pylori. As single tests, brush cytology and touch smear had high diagnostic accuracies with a Youdin J value of 1.79 and 1.78, respectively. CONCLUSION: The best method for diagnosis of H. pylori is a combination of the rapid urease test or brush cytology with histology. Brush cytology or touch smear are diagnostic tests of choice if a single test is desired.     

Evaluation of Helicobacter pylori with a stool antigen assay in frail, elderly patients

OBJECTIVE: Helicobacter pylori infection has not been studied thoroughly in elderly patients. The aim of this study was to evaluate the reliability of stool antigen assay (HpSA) in the assessment of H. pylori infection in hospitalized, frail, elderly patients. MATERIALS AND METHODS: The study population consisted of 85 consecutively recruited elderly patients (> or =65 years old) hospitalized between May 1999 and December 2001 with diagnostic indications for upper gastrointestinal endoscopy. Twenty-nine subjects had been receiving treatment with proton-pump inhibitors (PPIs), such as omeprazole (10-20 mg/day) for 2-15 days, and 56 were not receiving treatment. HpSA was evaluated versus UBT (urea breath test), serology and histology: patients with at least two positive results out of the latter three tests were considered positive for H. pylori infection, while patients with at least two negative tests out of three were considered negative. RESULTS: The sensitivity and specificity of HpSA in the 56 untreated patients were, respectively, 76% (true positives TP = 22; false negatives FN = 7) and 93% (true negatives TN = 25; false positives FP = 2). The sensitivity and specificity of HpSA in the 29 patients on PPI treatment were, respectively, 82% (TP = 9; FN = 2) and 83% (TN = 15; FP = 3). CONCLUSIONS: HpSA is an accurate, non-invasive and easy method for diagnosing H. pylori infection in elderly patients.     

Diagnostics of Helicobacter pylori infection in patients with peptic ulcer bleeding

BACKGROUND: In peptic ulcer bleeding, the sensitivity of H. pylori tests, in particular of the rapid urease test (RUT), has been reported to be insufficient. AIM: To validate the RUT, serology and the urea breath test were carried out in patients with bleeding peptic ulcers, and to study the influence of H. pylori suppressive treatment (HpSuT), i. e., antibiotics and proton pump inhibitors. PATIENTS AND METHODS: 123 consecutive patients (mean age 65.5 years) with a relevant bleeding from gastric or duodenal ulcers were prospectively tested for H. pylori infection by directs tests (RUT, histology, culture, urea breath test) and by IgG serology as an indirect test. Positive H. pylori status was defined by positive histology or culture. RESULTS: In patients without HpSuT during the preceding four weeks (N = 83), the sensitivity and specificity of RUT was 94 and 84 %, that of serology 83 and 68 % respectively. The sensitivity of urea breath test decreased from 82 to 60 % after even one day of HpSuT. In the overall group, the duration of HpSuT and preceding hospitalization were independent factors linked with negative results of all direct tests. CONCLUSIONS: In peptic ulcer bleeding, RUT combined with histology is an adequate diagnostic approach. However, false negative results have to be considered following even short-term HpSuT or hospitalization. Non-invasive diagnosis based on serology alone is inaccurate and should be complemented by the urea breath test prior to starting HpSuT.     

Lack of accuracy of the noninvasive Helicobacter pylori stool antigen test in patients with gastroduodenal ulcer bleeding

OBJECTIVE: Oral presentation at Digestive Diseases Week, San Francisco, California, May 2002. The antigen-based stool assay has proven to be accurate in diagnosing Helicobacter pylori infection in dyspeptic patients. We evaluated the H. pylori antigen-based stool assay (HpSA) in patients with peptic ulcer bleeding (PUB). METHODS: Thirty-six patients with PUB were endoscoped, and antral and corpus biopsy specimens were taken for rapid urease test (RUT), histology, and culture. The first stool sample after admission was collected for the HpSA test. The gold standard was defined as either positive culture or positive RUT and histology. If only RUT or histology was positive, this was defined as indeterminate. To evaluate cross-reaction with blood constituents, citrated blood samples from 10 healthy volunteers (nine H. pylori serology negative and one H. pylori serology positive) were assessed by the HpSA test. RESULTS:A total of 36 consecutive patients with PUB (21 male) with a mean age of 69.5 yr were included in the study. Using the gold standard, the sensitivity and specificity of the HpSA test were 100% and 52%, respectively. Citrated blood samples of three H. pylori negative and one H. pylori positive volunteer gave a positive result in the HpSA test, suggesting cross-reaction with blood con stituents. CONCLUSIONS: The HpSA test gave a high number of false- positive results in patients with PUB, probably because of blood constituents cross-reacting in the enzyme immunoassay. The HpSA test is not accurate for testing H. pylori infection in patients with PUB.     

A study of the relationship between Helicobacter pylori microbial susceptibility, 13C-urea breath test values

BACKGROUND/AIMS: Diagnostic methods for Helicobacter pylori (H. pylori) infection can be divided into invasive endoscopic methods and non-invasive methods. A typical and widely used non-invasive method is the 13C urea breath test (UBT). In this study, the possibility of a correlation between pre-treatment UBT values with H. pylori antimicrobial resistance is investigated. METHODOLOGY: The subjects were 119 consecutive patients who attended this hospital for H. pylori testing. Average age was 47.5 +/- 13.2 years, with a male:female ratio of 2.05:1. The diagnosis was gastric ulcer in 43 subjects, duodenal ulcer in 27, gastroduodenal ulcer in 21 and chronic gastritis in 28. Subjects underwent UBT as well as upper gastrointestinal endoscopy (UGITE). The diagnosis of H. pylori infection was examined by the results of culture, histological examination and the rapid urease test (RUT). The mean inhibitory concentration (MIC) was determined for each antimicrobial agent in the bacterial isolates that could be cultured. RESULTS: In this study, the sensitivity and specificity were excellent at 97.0% and 100% with a cut-off point of 3.5 per thousand for UBT respectively. Clarithromycin resistance was more common in the group with high UBT values. No correlation at all was seen between UBT values and metronidazole, sparafloxacin, cefaclor and amoxicillin susceptibility. CONCLUSIONS: It is possible that UBT values also tend to be higher in cases of CAM resistance.