Discrepancy between Helicobacter pylori stool antigen assay and urea breath test in the detection of Helicobacter pylori infection.

BACKGROUND: The reference diagnostic methods available for detection of Helicobacter pylori infection are either invasive (histology) or expensive and highly sophisticated (Urea Breath Test). A new enzyme immunoassay, which can be easily performed in any laboratory, has been developed to detect Helicobacter pylori in stool specimens (HpSA-Meridian Diagnostics, Cincinnati, USA). Aim of the study was to compare HpSA to Urea Breath Test. PATIENTS AND METHODS: A total of 125 patients (52 never treated for Helicobacter pylori infection and 73 after Helicobacter pylori eradication therapy) referring to our Department, underwent both tests within two weeks. RESULTS: Contrasting results between the two tests were found in 30% of cases: in 19% of the untreated patients and in 37% of the treated patients (p<0.001). The main discrepancy consisted in positive HpSA associated with negative Urea Breath Test. Mean HpSA value in such conditions was 0.273 optical density, while in patients with both positive tests, it was 1.192 optical density. In untreated, but not in treated patients, raising the HpSA cut off value significantly decreased the percentage of conflicting results. CONCLUSIONS: Some disagreement was detected between HpSA and Urea Breath Test results, especially in treated patients. Possible explanations for our findings are a low HpSA cut off value together with the identification of Helicobacter pylori coccoid forms by the immunoassay but not by the urease based Urea Breath Test. The higher percentage of discrepancy detected in treated patients might support this hypothesis.     

Helicobacter pylori antigen stool test and 13C-urea breath test in patients after eradication treatments

OBJECTIVES: Current guidelines recommend either the urea breath test (UBT) or the Helicobacter pylori antigen stool test (HpSA) for monitoring H. pylori infection. The aim of this study was to evaluate the agreement between the two tests in patients after treatment. METHODS: After eradication treatments, patients were tested with both UBT and HpSA. Cut-off values (delta value over baseline at 30') for UBT were positive (> or = 5 per thousand), indeterminate (3.01-4.99 per thousand), and negative (< or = 3 per thousand). Cut-off values (absorbance at 450 nm) for HpSA test were positive (> or = 0.160), indeterminate (0.159-0.140), and negative (< 0.140). Patients with either discordant or indeterminate tests underwent repeat endoscopy with multiple gastric biopsies for rapid urease test (RUT), culture, histology, and immunohistochemistry to detect H. pylori and to assess the ratio between coccoid and bacillary forms. RESULTS: A total of 458 patients were studied. Of these, 422 (92.2%) had concordant tests, three (0.6%) indeterminate tests (one on UBT and two on HpSA), and 33 (7.2%) discordant tests. A total of 28 patients (25 with discordant and three with indeterminate tests) underwent endoscopy. The HpSA was inaccurate in 24 cases (18 false negative, four false positive, and two indeterminate results), whereas the UBT was inaccurate in four cases (two false positive, one false negative, and one indeterminate results). Biopsy-based tests showed no bacillary or coccoid forms in all five endoscoped patients who were negative on UBT and positive on HpSA, but in one in whom the ratio between coccoid and bacillary forms was 3:1 in the antrum and corpus. CONCLUSIONS: UBT and HpSA test give discordant or indeterminate results in nearly 8% of patients after treatment. The HpSA test is less accurate than the UBT. Coccoid forms do not cause false positive HpSA results.     

粪便抗原检测诊断幽门螺杆菌现症感染

目的 评价应用免疫酶联吸附试验(ELISA)检测粪便中幽门螺杆菌(Helicobacter pylori)抗原诊断H.pylori现症感染的敏感性和特异性。方法 应用^14C呼气试验以及幽门螺杆菌粪便抗原(HpSA)试验，对100例因上消化道不适就诊，怀疑有H.pylori感染的患者进行检测，观察两种检查的符合率。结果 ^14C呼气试验和HpSA同时阳性者38例，^14C呼气试验阳性而HpSA阴性者4例；^14C呼气试验和HpSA同时阴性者57例，^14C呼气试验阴性而HpSA阳性1例。以^14C呼气试验作为金标准计算，HpSA检测方法的敏感性为90．48％，特异性为98．28％。结论 幽门螺杆菌抗粪便原检测与^14C呼气试验有较高的符合率，而且简便易行，不需特殊设备，解决了无法进行呼气试验的婴幼儿和有肺部疾患者的非侵人性幽门螺杆菌现症感染诊断问题，是一种非侵入性幽门螺杆菌现症感染诊断的新方法。     

Current role of Helicobacter pylori stool tests

Helicobacter pylori stool tests are an accurate and noninvasive tool to assess H. pylori status before and after treatment. We are convinced that the current technical shortcomings of H. pylori stool tests, i.e. inter-test variability and reduced specificity after treatment, can be overcome in the near future. The availability of an office-based stool test would offer a considerable advantage since it could be performed in any private practice without further delay. However, it remains to be seen whether the reluctance of patients to collect stool specimens will have an impact on its general use.     

Usefulness of the Helicobacter pylori stool antigen test for detection Helicobacter pylori infection

Several diagnostic tests are available for evaluating Helicobacter pylori (H. pylori) infection: histological examination, culture of gastric biopsy specimens, rapid urease test, urea breath test and serology. In this study, we assessed the reliability of a newly developed enzyme immunoassay HpSA (H. pylori Stool Antigen) kit for detecting H. pylori antigen in stool. Eighty-five patients (50 males, 35 females; mean age 41.6 +/- 9.8 years) with dyspeptic symptoms who were examined by upper gastrointestinal endoscopy. The patients with a history of previous treatment with proton pump inhibitors, bismuth compounds or antibiotics were excluded. During the endoscopic examination biopsies were taken from antrum and corpus for rapid urease test and histological examination. Stool specimens were submitted to the laboratory and HpSA test was performed. H. pylori was considered in condition with rapid urease test and histopathological examination for H. pylori positive. Forty-six of 85 patients were positive and remaining 39 patients were negative for H. pylori with the rapid urease test and pathologic evaluation. When 0.160 was adopted as the cut-off value, in accordance with the manufacturer's recommendations; stool antigen has been detected in 45 of the 46 H. pylori positive patients. The sensitivity and specificity of HpSA test were 97.8%, 94.9% respectively. These results indicate that HpSA is a highly reliable diagnostic method for H. pylori infection.     

Gastroduodenal Helicobacter pylori infection diagnosed by Helicobacter pylori stool antigen is related to atherosclerosis

OBJECTIVE: The causative relation between Helicobacter pylori (H. pylori) and atherosclerosis has been determined as seropositivity or determination of H. pylori from atherome plaques by molecular methods. The site of entrance and the reservoir of the bacteria in the body is still a subject of discussion. In this study Helicobacter pylori stool antigen (HpSA) which shows gastrointestinal system colonization and infection with high specificity and sensitivity was determined in atherosclerotic, ectatic and angiographically normal groups. METHODS AND RESULTS: A total of 62 patients was categorized according to diagnostic coronary angiography as 12 had normal coronary arteries, eight had one, 18 had two, and 12 had three atherosclerotic coronary arteries. Twelve patients had ectatic vessels. There were 27 (44%) HpSA positive and 35 (56%) HpSA negative patients. There was a statistically significant relation between HpSA positivity and the degree of vessel involvement in coronary artery disease (CAD) patients, essentially between the group with three vessels (83%) obstructed and the normal group (25%). Ectatic vessel group had a higher incidence (50%) of HpSA positivity compared to the control group but not enough for statistical significance. CONCLUSIONS: The results indicate that gastrointestinal system H. pylori colonization increases the risk of atherosclerosis. We may speculate that the reservoir and spread of H. pylori is via gastrointestinal tract. Studies may be performed to detect whether gastrointestinal tract H. pylori infection treatment will decrease the risk of coronary artery damage caused by H. pylori.     

Helicobacter pylori stool antigen (HpSA) test--a simple, accurate and non-invasive test for detection of Helicobacter pylori infection

BACKGROUND/AIMS: To access the reliability of a newly developed test, the Helicobacter pylori (H. pylori) stool antigen (HpSA) test was used for detection of H. pylori infection. METHODOLOGY: Stool specimens were collected from 33 consecutive patients (19 males and 14 females, age range: 16-73 years, mean: 49 years) who received upper gastrointestinal endoscopic examination for gastrointestinal symptoms. The H. pylori status was evaluated based on six different tests: culture, histology, biopsy urease test, 13C-urea breath test (13C-UBT), serology, and HpSA test. A commercial kit using an enzyme-linked immunosorbent assay examined HpSA in the stool. H. pylori status was defined as positive when the culture was positive or concordance of three of the other four tests (histology, biopsy urease test, 13C-UBT, and serology) was positive. RESULTS: Twenty patients were diagnosed as H. pylori-positive. The HpSA test was positive in 19 patients and negative in 14 patients. The sensitivity and specificity were 95.0% and 100%, respectively. The overall accuracy rate was 96.3%. CONCLUSIONS: The HpSA test is a new, simple, non-invasive method for accurate diagnosis of H. pylori infection.     

Helicobacter pylori Infection and Blood Groups

Objectives : Bacterial attachment is a prerequisite for colonization of the gastric epithelial surface. Recently, it was demonstrated that the receptor for Helicobacter pylori is the blood group antigen Lewis h, which is exposed only in blood group O. We prospectively examined the prevalence of blood groups in H. pylori-positive and -negative patients. To avoid a genetic bias, we compared blood group prevalence of our patients with the general population of Israel. Methods : In the 187 consecutive patients we studied, in addition to regular upper endoscopy, H. pylori status and blood group. Exposure to H. pylori was diagnosed when the results of two or more of three methods were found to the positive. Results: Exposure was found in 123 patients and 64 were negative. The groups were similar in average age and origin, and no significant difference was demonstrated for blood group. Blood group distribution between any given origin was not significantly different in our patients and in a sample of 182,701 blood donors. Conclusions : Positivity for H. pylori was not associated with blood group O. Our observation does not support the conclusion that the receptor for H. pylori in the gastric mucosa is the blood group antigen Lewis b.     

Accuracy of Helicobacter pylori stool antigen for the detection of Helicobacter pylori infection in dyspeptic patients

AIM: The premier platinum Helicobacter pylori (H pylori) stool antigen (HpSA) test is an enzyme immunoassay (EIA) that detects an H pylori antigen present in human stools. However, at present there is no uniformity about the cut off level required to consider the test as positive or negative. So we need the cut off level for our local population. The aim of this study was to evaluate the HpSA for the detection of H pylori infection in dyspeptic patients and to determine the sensitivity, specificity of the HpSA test in the diagnosis of H pylori infection, as compared to other standardized diagnostic techniques. METHODS: Sixty-three dyspeptic patients were selected from patients who came to the Division of Gastrointestinal Clinic in Cipto Mangunkusumo Hospital, Jakarta, Indonesia. H pylori infection was confirmed in all patients by histology and rapid urease test (CLO test). Positive results for H pylori were based on positive results from both rapid urea test and microscopic detection of H pylori. Stool specimens were analyzed for H pylori antigen using HpSA immunoassay. RESULTS: A total 63 patients consisted of 31 (49.2%) males and 32 (50.8%) females ranging in ages between 16 and 73 years with a mean age of 42.4+/-15 years. The mean age of men was 43.2+/-15.7 years and women was 41.6+/-14.4 years. Endoscopic findings in this study included gastric cancer 1.6%, peptic ulcer 4.8%, duodenal ulcer 7.9%, esophagitis 6.3%, gastritis 77.7%, and gastroduodenitis 4.8%. According to the predefined study criteria, 6 (9.5%) of 63 patients were positive for H pylori. In the diagnosis of infection, the area under the receiver operating characteristic (ROC) curve for the HpSA test was 0.722 (95% CI, 0.518-0.927). Using a cut-off value of 0.274 instead of 0.16 (as recommended by the manufacturer) the sensitivity and the specificity were 66.7% and 78.9% respectively. CONCLUSION: The HpSA stool test, using a cut-off value of 0.274, may be useful for the primary diagnosis of H pylori infection, its specificity is similar to other standard tests but its sensitivity was lower.     

Effect of proton pump inhibitors and antacid therapy on 13C urea breath tests and stool test for Helicobacter pylori infection

OBJECTIVE: There is uncertainty about the best method of testing patients for Helicobacter pylori (H. pylori) infection while they are taking proton pump inhibitors. The aim of this study was to determine: (i) if the decreased sensitivity of the urea breath test during proton pump inhibitor is corrected by different techniques for breath testing and (ii) if the sensitivity of stool test is decreased with the administration of proton pump inhibitors. METHODS: Prospective randomized single-blind study was performed in a tertiary care university hospital. Out of 72 H. pylori infected patients endoscoped for upper abdominal symptoms 48 were randomized to proton pump inhibitors (omeprazole 20 mg each day or esomeprazole 40 mg each day) and 24 to antacid (aluminum hydroxide 800 mg each day) for 14 days. Several breath tests (standard 75 mg (13)C-UBT with citric acid, with orange juice, a tablet breath test with 100 and 50 mg of (13)C), and a stool test were carried out. Baseline samples were collected before and after treatment. RESULTS: The baseline sensitivity for all breath tests was 100% in both groups; for stool test it was 97.8% (95% CI: 88.7-96.6) and 90% (95% CI: 69.9-97.2) in the proton pump inhibitor and antacid group, respectively. After treatment, the sensitivity of tests was significantly low (UBTs range: 77.1%-85.4%; stool test: 83%; 95% CI: 63.9-91.1), while it was unchanged in the antacid group. CONCLUSIONS: False negative breath and stool tests are equally common in patients taking proton pump inhibitors. Antacids do not impair the sensitivity of the breath tests or the stool test.     

幽门螺杆菌粪便抗原检测在体检人群中的应用价值

[目的]探讨中老年人群幽门螺杆菌(HP)感染情况及HP粪便抗原(HPSA)在体检中的应用价值.[方法]对1 774例≥40岁人群粪便标本进行HPSA检测,分析HP感染及其与胃病症状的关系.[结果]1774例中HP阳性者251例,HP阳性率14.15％; 40～～50岁者HP阳性率最高(19.71％),＞80岁者阳性率最低(9.04％);HP感染与吸烟饮酒的生活习惯及胃部症状无关.[结论]生活条件良好的中老年群体HP阳性率呈收敛趋势,与吸烟、饮酒无明显关系,无症状人群应重视HPSA监测,HP阳性人群应行胃镜检查.     

幽门螺杆菌粪便抗原试验检测幽门螺杆菌感染的临床评价

目的 评价一种新的酶免疫法——幽门螺杆菌(HP)粪便抗原(HPSA)试验检测HP感染和监测HP根除治疗的可靠性。方法 未接受过抗HP治疗的患者分为2组，A组331例，无胃部手术史；B组65例，胃大部切除术后。2组患者因上消化道症状而接受胃镜检查，以胃黏膜活检标本快速尿素酶试验(RUT)和组织学检查(W-S染色)联合检测HP作为“金标准”，对HPSA试验的准确性进行评价，并与另一非侵入性的^13C-尿素呼气试验(^13C-UBT)加以比较。此外，A组中HP阳性的56例患者(C组)给予三联根除治疗1周，分别于停药后第1、7、14、21、28天收集粪便标本进行HPSA测定。于停药后第28天测定^13C-UBT，并以此为标准，评价HPSA试验的准确性。结果 A组患者经“金标准”诊断HP阳性175例，阴性156例。HPSA试验的敏感性为95，4％，特异性为91．0％，与^13C-UBT比较差异无统计学意义。B组患者中，经“金标准”诊断HP阳性30例，阴性35例。月psA试验敏感性为90．0％，^13C-UBT的敏感性为66．7％。HPsA试验的敏感性明显优于^13C-UBT(P＜0．05)。C组患者于停药后第28天经^13C-UBT诊断HP阳性16例，阴性40例。HPSA于停药后第1天54例阴性，此后随时间推移，未成功根除病例陆续转为阳性，而成功根除病例仍大部分保持在阴性范围，仅少数病例出现假阳性。停药后第28天的准确性最高(92．9％)。结论 HPSA试验是一种可靠的非侵入性检测方法，对于抗HP治疗前、后患者HP感染的诊断均有较高的准确性。对于胃大部切除术后的患者亦有较高的诊断价值。     

Clinical value of Helicobacter pylori stool antigen test,ImmunoCard STAT HpSA，for detecting Hpylori infection

AIM: To evaluate the reliability of the Helicobacter pylori stool antigen test, ImmunoCard STAT HpSA, for detecting H pylori infection. METHODS: Stool specimens were collected from 53 patients who received upper endoscopy examination due to gastrointestinal symptoms. ImmunoCard STAT HpSA was used to detect H pylori stool antigens. H pylori infection was detected based on three different tests: the urease test, Warthin-Starry staining and culture. H pylori status was defined as positive when both the urease test and histology or culture alone was positive. RESULTS: Sensitivity, specificity, positive predictive and negative predictive values and the total accuracy of ImmunoCard STAT HpSA for the diagnosis of H pylori infection were 92.6% (25/27), 88.5% (23/26), 89.3% (25/28), 92% (23/25) and 90.6% (48/53), respectively.CONCLUSION: The stool antigen test, ImmunoCard STAT HpSA, is a simple noninvasive and accurate test for the diagnosis of H pylori infection.