Salivary immunoglobulin G assay to diagnose Helicobacter pylori infection in children

An in-house enzyme-linked immunosorbent assay (ELISA) for measurement of Helicobacter pylori-specific immunoglobulin G (IgG) and IgA in saliva was evaluated by comparison with histopathologic (Giemsa staining) and biochemical (urease quick test) examination of gastric biopsy specimens obtained from 112 children referred for diagnostic gastroscopy. Serum H. pylori IgG was also measured in a subgroup of 50 children by the same ELISA. Salivary H. pylori IgG levels were significantly higher in H. pylori-positive (n = 57) than in H. pylori-negative (n = 55) children (P < 0.001). The sensitivity and specificity of the salivary IgG test were 93 and 82%, respectively; the positive and negative predictive values were 84 and 92%, respectively; and the accuracy was 87.5%. Salivary H. pylori IgA did not distinguish H. pylori-positive from H. pylori-negative children. The performance of serum H. pylori IgG was slightly (3 to 6%) better than that of salivary H. pylori IgG. The salivary IgG test can be considered a useful tool for the screening of H. pylori infection in children.     

Salivary-specific immunoglobulin G in the diagnosis of Helicobacter pylori infection in dyspeptic patients

OBJECTIVES: Helicobacter pylori infection is arguably the most common chronic bacterial infection in humans. The high prevalence and the association with peptic ulceration and gastric cancer indicate that simple, noninvasive methods for diagnosis of the infection are needed. In this study, the accuracy of salivary diagnosis for H. pylori infection was assessed. METHODS: Saliva and serum samples of 152 dyspeptic patients were tested for H. pylori IgG and IgA by an in-house ELISA. All patients underwent gastroscopy with biopsy. RESULTS: One hundred thirty-one patients (86%) were found to be H. pylori positive on histology. Duodenal ulcer was found in 67 patients; 85 had no macroscopic lesion. Salivary and serum H. pylori IgG as well as serum H. pylori IgA titers were significantly higher in H. pylori-positive than in H. pylori-negative patients. The sensitivity and specificity of salivary H. pylori IgG were 82% and 71%, respectively; the positive and negative predictive values were 95% and 40%, respectively; and the accuracy 81%. The corresponding figures for serum H. pylori IgG were 97% and 91%; 98% and 83%; and 96%. Those for serum H. pylori IgA were 80% and 52%; 91% and 30%; and 76%. The sensitivity of salivary H. pylori IgG in detecting duodenal ulcer was 83% (56/67) that of serum H. pylori IgG was 97% (65/67) (odds ratio = 0.15; confidence interval = 0.02-0.8; p = 0.02). CONCLUSIONS: Salivary H. pylori IgG was a fairly sensitive and accurate indicator of gastric H. pylori colonization, with a high positive predictive value in our population. Data, however, suggest that salivary H. pylori IgG measurements do not compare favorably with serology.     

A review of esthetic alternatives for the restoration of anterior teeth

Helicobacter pylori infection is an important cause of peptic ulcer disease and chronic gastritis. Infection with this bacterium stimulates the production of immunoglobulin (Ig) G antibody. Salivary IgG antibody tests to detect H pylori infection offer a convenient and noninvasive method of diagnosis. To evaluate an IgG salivary antibody kit, saliva was collected from 157 out-patients with dyspepsia referred for endoscopy to a tertiary centre. A salivary IgG ELISA antibody assay was performed using the Helisal Helicobacter pylori (IgG) assay kit, and at least four gastric biopsies were obtained. H pylori infection was confirmed by demonstration of the organism on Warthin-Starry silver stain (sensitivity 85%, specificity 55%). The prevalence of infection with H pylori was 30%. When the analysis was redone, excluding those treated with eradication therapy, the results were similar (sensitivity 86%, specificity 58%). The positive predictive value of the assay was 45% and the negative predictive value was 90%. Despite the ease of sampling, the assay used has limited diagnostic utility, lacking the predictive value to indicate which patients referred with dyspeptic symptoms to a tertiary care setting are infected with H pylori.     

Possible role of Helicobacter pylori infection in early gastric cancer development

BACKGROUND: Gastric cancer is the most frequently diagnosed malignancy in Japan. The possible relationship between Helicobacter pylori infection and gastric cancer in Japan was evaluated. METHODS: H. pylori infection was identified by the presence of anti-H. pylori IgG. The frequency of H. pylori infection was compared in 213 patients with gastric cancer and the same number of asymptomatic control subjects matched for age and sex. RESULTS: The presence of IgG antibody to H. pylori was significantly more prevalent (P < 0.001) in those with gastric cancer compared with asymptomatic control subjects (88.2% versus 74.6%). H. pylori positive rates were significantly greater in patients with the intestinal type (90.4%, P < 0.001) and diffuse type (86.4%, P < 0.05) of gastric cancer than in control subjects. Ninety-three percent of the patients with early gastric cancer tested positive for H. pylori (P < 0.001 compared with control subjects), whereas no significant difference was observed between those with advanced gastric cancer and control subjects. The intestinal type of early gastric cancer showed only the significantly increased frequency of high titer (optical density > 1.50) of H. pylori IgG antibody (P < 0.001) compared with control subjects without cancer. CONCLUSIONS: These results suggest that H. pylori infection may be associated with the development of early gastric cancer in Japan.     

Evaluation of eight commercial kits for Helicobacter pylori IgG antibody detection

Eight commercial kits and an in-house ELISA for detection of IgG antibodies against Helicobacter pylori were evaluated for their use in diagnosis of H. pylori infection and in epidemiological research: Helico-GTM (Porton-Cambridge), G. A. P. test (Bio-Rad), H. pylori antibodies ELISA (Biometra), Anti-H. pylori IgG EIA (Roche), 2nd generation H. pylori EIA (Roche), Anti-H. pylori MTP-assay (Roche), Pylori stat test kit (Whittaker), Pyloriset latex agglutination kit (Orion), and the in-house ELISA based on heat-stable antigens. Fifty-four patients with dyspepsia (31 H. pylori positive by culture or microscopy) and 68 asymptomatic persons were tested. Sensitivities for the eight kits were 71%, 77%, 90%, 84%, 87%, 94%, 90%, 87%, and 87%, specificities were 74%, 65%, 74%, 74%, 83%, 83%, 70%, 65%, and 65%, respectively. For epidemiological use the estimated seroprevalence varied within approximately 15% in all age groups. Sensitivities and specificities obtained in different studies reveal as great differences in the results with the same kit as between results obtained with different kits in the same study. Kits with the highest sensitivities tend to be the same in all studies. It is therefore more important to test a kit in the population to which it is to be applied than to choose a specific kit.     

Antibodies against Helicobacter pylori were detected in the cerebrospinal fluid obtained from patients with Guillain-Barré syndrome

We examined the antibodies against Helicobacter pylori proteins in the cerebrospinal fluid (CSF) of 7 patients with Guillain-Barré syndrome (GBS). Crude H. pylori antigens, fractionated heat shock protein (HSP), and urease B (UB) from H. pylori antigens were separated by SDS-PAGE. With Western blot analysis, four of seven CSF samples had several IgG antibodies against H. pylori proteins, including HSP and UB. No cross reactivity against Campylobacter jejuni was observed. These antibodies may be involved in the immune responses of patients with GBS.     

Association of Helicobacter pylori infection with elevated serum lipids

Helicobacter pylori causes a chronic gastric infection, which has been associated with coronary heart disease. To evaluate the mechanisms of this association, we studied whether the infection affects serum lipid levels as previously shown in acute infections. We analysed the serum samples of 880 males who participated in a reindeer herders' health survey in Northern Finland in 1989. H. pylori IgG and IgA antibodies were measured by enzyme-linked immunosorbent assay and triglyceride, total cholesterol and high-density lipoprotein cholesterol concentrations by routine enzymatic methods. A total of 52% of the subjects were positive for both H. pylori specific IgG and IgA and 31% were antibody-negative. The serum triglyceride and total cholesterol concentrations were significantly higher in the males with positive IgG and IgA antibody titres for H. pylori than in the males with no signs of infection (1.20 vs. 1.03 mmol/l, P < 0.001 and 6.59 vs. 6.11 mmol/l, P < 0.001, respectively). The associations remained statistically significant in non-smokers after the adjustment for age, body mass index (BMI) and social class. The finding supports the hypothesis that chronic infections may modify the serum lipid profile in a way that increases the risk of atherosclerosis.     

Helicobacter pylori infection in patients with chronic pancreatitis and duodenal ulcer

BACKGROUND: The prevalence of duodenal ulcer is high in patients with chronic pancreatitis. Patients with simple duodenal ulcer without chronic pancreatitis are mostly Helicobacter pylori-infected, and the prevalence of IgG seropositivity is > 95%. The prevalence of H. pylori infection in patients with chronic pancreatitis is not known. METHODS: IgG antibodies against H. pylori were measured in a cross-sectional survey of consecutive patients who had their exocrine pancreas function examined with a Lundh meal test in the period 1988-95 and in a control group of patients with simple duodenal ulcer. RESULTS: Twenty-seven per cent of the patients with chronic pancreatitis had duodenal ulcer during the observation period. The prevalence of IgG antibodies against H. pylori was 22% in patients with chronic pancreatitis without duodenal ulcer as compared with 27% with non-organic abdominal pain. The prevalence of IgG antibodies against H. pylori was 60% in patients with chronic pancreatitis complicated by duodenal ulcer as compared with 86% in controls with simple duodenal ulcer. CONCLUSIONS: H. pylori infection contributes but may not be the only cause of duodenal ulcer in patients with chronic pancreatitis.     

Developing a critical pathway for orientation

In an attempt to establish the etiologic role of Helicobacter pylori (H. pylori) in gastric and/or duodenal pathology, 169 patients were tested and compared with a control group of 25 healthy subjects, for a total of 194 subjects. Data on sex, age, familiarity, smoking, coffee and alcohol habits were collected and each patient underwent histological, microbiological and immunological tests. 80 (41.2%) subjects were found positive to H. pylori. This bacterium was detected in 53.3% of patients with gastric ulcer while IgG were found in 86.7%; in 50% of patients with chronic atrophic gastritis while IgG were detected in 80%; in 48.5% of patients with duodenal ulcer while IgG were found in 87.9%; in 41.8% of patients with superficial chronic gastritis while IgG were detected in 80.2%. In the control group of healthy patients H. pylori was found in 28% of patients while IgG were detected in 62.5%. The results do not confirm a direct clear-cut correlation between this microorganism and the pathologies studied.     

Immunochemical properties of a 60 kDa cell surface-associated heat shock-protein (Hsp60) from Helicobacter pylori

Western blot analysis (immunoblotting) of cell surface-associated proteins from Helicobacter pylori confirmed our previous findings that binding of human IgG is a common property (among H. pylori strains). Purification of the IgG-binding proteins (IGBP) was achieved by two purification steps, affinity chromatography on IgG-Sepharose and nickel chelate affinity chromatography. SDS-PAGE and immunoblotting analysis revealed a 60 kDa protein with affinity for peroxidase labeled human IgG. Solid phase binding assays showed that IgG binds to an immobilized protein (IGBP). The 60 kDa IGBP binds human IgG1, IgG3 and IgM. Binding could be inhibited by the kappa chain of the human IgG, but not with its Fc fragment, nor with IgA or IgM. In addition, rabbit polyclonal antibodies raised against the 60 kDa IGBP blocked IgG binding. Monoclonal antibodies, specific to the Hsp60 heat shock protein of H. pylori recognized the 60 kDa IGBP as revealed by immunoblotting analysis, both in crude preparations and in the purified fractions.     

Local immune response in Helicobacter pylori-infected cats and identification of H. pylori in saliva, gastric fluid and faeces

Helicobacter pylori-infected cats were screened by culture and polymerase chain reaction (PCR) for the presence of H. pylori in salivary secretions, gastric juice, gastric tissue and faeces. H. pylori was cultured from salivary secretions in six of 12 (50%) cats and from gastric fluid samples in 11 of 12 (91%) cats. A 298 base pair polymerase chain reactions (PCR) product specific for an H. pylori 26000 MW surface protein was amplified from dental plaque samples from five of 12 (42%) cats and from the faeces of four of five (80%) cats studied. Analyses of serum and mucosal secretions by enzyme-linked immunosorbent assay (ELISA) revealed an H. pylori-specific immunoglobulin G (IgG) response, and elevated IgA anti-H. pylori antibody levels in salivary and local gastric secretions. Immunohistochemical analyses of gastric tissue revealed the presence of IgM+ B cells assembled into multiple lymphoid follicles surrounded by clusters of CD4+ and CD8+ T cells. The lamina propria also contained single cells or aggregates of IgA+ and IgM+ B cells. These observations show that H. pylori can be identified in feline mucosal secretions, and that a localized IgA immune response develops in gastric tissue of H. pylori-infected cats. The findings suggest a zoonotic risk from exposure to personnel handling H. pylori-infected cats in vivaria.     

High prevalence of Helicobacter pylori antibodies in an institutionalized population: evidence for person-to-person transmission

OBJECTIVE: To evaluate the prevalence of H. pylori antibodies in mentally and physically handicapped adults living together in a long-term care facility. METHODS: One hundred twenty-two institutionalized subjects from six living areas were compared to a normal representative Caucasian population obtained by random sampling from the urban population area of Melbourne. Serum samples from 1977 and 1989 from 122 subjects were tested for H. pylori antibody by an ELISA technique. The data were analyzed by Student's t test, chi 2 test and logistic regression. RESULTS: Ninety-two of the 122 subjects (75%) from whom sera was collected in 1989 were seropositive for H. pylori, compared with only 23% in age- and sex-matched control subjects (p < 0.0001). The prevalence of H. pylori antibodies in 1977 was 34% (42/122). Of the remaining 80 seronegative subjects, 51 (61.4%) converted to became positive in the 12-yr interval. The annual seroconversion rate was 7.4%, with an average of 4.25 newly positive subjects each year. The prevalence of H. pylori in 1989 was significantly higher than in 1977 after adjustment for age (odds ratio 2.39, 95% CI 1.1-5.3, p = 0.03). CONCLUSIONS: H. pylori antibodies are significantly more prevalent in institutionalized adults compared with controls from the general population. These data support the hypothesis that H. pylori is acquired by either fecal-oral or oral-oral transmission.     

Immunoglobulin A antibodies to Helicobacter pylori

Serological testing for immunoglobulin G (IgG) antibodies to Helicobacter pylori has proven useful in supporting the diagnosis of infection with this organism, but the clinical value of IgA antibodies in H. pylori-related gastritis remains controversial. The purpose of our study was to determine the frequency of IgA-positive IgG-negative patients with symptoms of gastrointestinal (GI) disorders, thus assessing the clinical utility of IgA testing for H. pylori-related gastritis. It was found previously that the frequency of infected individuals in this category (IgA positive and IgG negative) is about 2%, but a large number of IgG-negative patients with GI disorders suggestive of H. pylori infection have not been investigated until now.     

Helicobacter pylori CagA antigen antibodies

BACKGROUND: CagA antigen of Helicobacter pylori is highly immunogenic in humans. There is an increasing evidence that infection with CagA-positive strains is related to the development of peptic ulcer disease, atrophic gastritis, or gastric cancer. The aim of our study was to assess seropositivity to CagA in a group of 95 clinically symptomatic adults who underwent gastroduodenoscopy and to correlate results to their disease characteristics. METHODS AND RESULTS: Serum immunoglobulin G antibodies to CagA detected by ELISA kit (Helicobacter p120, Viva Diagnostika, Germany) were compared to standard IgG specific antibodies against a pool of H. pylori antigens Synelisa Pin plate, ELIAS, Germany). Immunoglobulin G antibodies to CagA were present in 5/31 (16%) serum samples from H. pylori negative persons and 10/28 (36%) serum samples from H. pylori positive patients without peptic ulcer disease compared with 8/11 (73%) H. pylori positive patients with peptic ulcer disease in the past, 11/13 (85%) H. pylori positive patients with duodenal ulcers or duodenitis and 4/5 (80%) H. pylori positive (1/7, 14% H. pylori negative) serum samples from patients with gastric resection for peptic ulcers in the past. Serum levels of antibodies to CagA in the groups of patients with peptic ulcer disease in the past, with present duodenal ulcers of duodenitis and in H. pylori infected patients with gastric resection were significantly higher then those of H. pylori infected patients without peptic ulcer disease (P < 0.05). On the other hand, there was no significant difference in the presence of the specific antibodies against at pool of H. pylori antigens between these four groups. CONCLUSIONS: These data suggest that serologic response to the CagA antigen is more prevalent in H. pylori positive persons with present or past peptic ulceration than among infected persons without peptic ulcer disease. The presence of antibodies to CagA in H. pylori positive persons may be useful for the identification of patients with higher risk or more severe disease.     

Helicobacter pylori infection in a randomly selected population, healthy volunteers, and patients with gastric ulcer and gastric adenocarcinoma. A seroprevalence study in Taiwan

To investigate the association of Helicobacter pylori and gastric ulcer and adenocarcinoma, IgG antibodies against H. pylori were examined in 823 randomly selected subjects, 92 healthy volunteers, 117 patients with gastric ulcer, and 148 with gastric adenocarcinomas in Taiwan, where the prevalence of gastric adenocarcinoma is high. The seropositivity of this population in Taiwan was 54.4%. Gastric ulcer patients had a higher seropositivity (83.8%) than healthy volunteers (62.0%) and gastric adenocarcinoma patients (62.2%) (P < 0.001). Gender difference, blood type, and habit of smoking were not associated with the seroprevalence in any study groups. Gastric ulcer coexistent with duodenal ulcer had a higher seropositivity (94.7%) (P < 0.05). The seropositivity of H. pylori in gastric adenocarcinoma patients was higher than in healthy volunteers only in younger age and was not associated with histologic type, invasion, and location of major tumors. The results reemphasize the association of H. pylori infection with gastric ulcer but not with gastric adenocarcinoma in Taiwan.     

Evaluation of the FlexSure HP whole blood antibody test for diagnosis of Helicobacter pylori infection

OBJECTIVE: Rapid, inexpensive, reliable tests are needed to facilitate the diagnosis of Helicobacter pylori infection. We evaluated the accuracy of the new FlexSure HP whole blood test (SmithKline Diagnostics, Inc.), a rapid, qualitative in-office test for the detection of antibodies to H. pylori utilizing whole blood obtained from a fingerstick. METHODS: Five North American sites enrolled patients not previously treated for H. pylori who underwent upper endoscopy. Patients had not received antibiotics, bismuth, or proton pump inhibitors within 4 wk before study enrollment. Bacterial infection was established by the presence of H. pylori in gastric biopsies (minimum of two) or positive rapid urease test of antral tissue. The presence of IgG antibodies was determined using FlexSure HP whole blood tests with blood obtained by fingerstick and FlexSure HP serum and ELISA (HM-CAP) tests with serum obtained from venipuncture. RESULTS: Three hundred ninety-three patients were enrolled (56% male; mean age, 46.8 +/- 16.0 yr). H. pylori infection was present in 187 (48%). Compared with the standard of histology and rapid urease test, sensitivity for FlexSure HP whole blood, FlexSure HP serum, and HM-CAP EIA were, respectively, 84%, 90%, and 95% (p < 0.05 compared with FlexSure HP whole blood). There were no statistical differences in specificity or overall accuracy between the three tests. CONCLUSIONS: FlexSure HP whole blood demonstrated an accuracy not significantly different from the FlexSure HP serum test but had sensitivity significantly lower than the HM-CAP EIA. FlexSure HP whole blood may be useful for in-office H. pylori diagnosis.     

Peptides derived from collagen: new biochemical markers of bone metabolism]

OBJECTIVE: To study a possible association of the Helicobacter pylori seroprevalence with ABO(H) and Lewis (a,b) blood group phenotypes in blood donors. DESIGN: A cross-sectional study of blood donors using ABO(H) and Lewis (a,b) blood group phenotype as predictors. METHODS: ABO(H) and Lewis (a,b) blood group phenotyping was performed with monoclonal antibody. The H. pylori immunoglobulin G (IgG) antibody relative activity was evaluated by enzyme-linked immunosorbent assay (ELISA) using acid glycine extract from H. pylori. SUBJECTS: One hundred and fifty-nine randomly selected blood transfusion donors. RESULTS: The individuals with Lewis (a+b-)/non-secretor phenotype showed a significantly higher proportion of the H. pylori-seronegative subjects and a lower IgG immune response to H. pylori antigens as compared with the individuals of Lewis (a-b+)/secretor phenotype. CONCLUSION: The Lewis (a,b) histo-blood group antigens are implicated in the mechanisms of naturally occurring resistance to H. pylori infection.     

Urease-specific monoclonal antibodies prevent Helicobacter felis infection in mice

Experiments were performed to determine the antigenic specificity of a monoclonal antibody (immunoglobulin A [IgA] 71) previously demonstrated to neutralize the ability of Helicobacter felis to colonize mice. Immunoprecipitation of radiolabeled H. felis outer membrane proteins with IgA 71 revealed specificity for a 62-kDa protein. Another of our monoclonal antibodies, IgG 40, precipitated a protein of similar molecular weight. IgA 71 but not IgG 40 also precipitated purified recombinant H. pylori urease. The antigenic specificity of both antibodies was confirmed to be urease by the ability of each to select Escherichia coli clones expressing the H. felis urease genes. The two antibodies were shown to bind nonoverlapping epitopes in a competition enzyme-linked immunosorbent assay. Both IgA 71 and IgG 40 could effectively neutralize H. felis infectivity by incubating the bacteria with the antibodies prior to oral administration to naive mice. The mechanism of protection does not appear to be inhibition of urease activity, as IgA 71 does not inhibit the conversion of urea to ammonia by H. pylori urease in vitro. These results support a protective role for the secretory humoral immune response in Helicobacter immunity and provide further evidence that the urease enzyme can serve as a protective antigen.     

Human antibody response to Helicobacter pylori lipopolysaccharide: presence of an immunodominant epitope in the polysaccharide chain of lipopolysaccharide

We have examined the antibody response to Helicobacter pylori lipopolysaccharides (LPS) in humans. We used sera from patients with gastroduodenal diseases and healthy adults infected or not infected with H. pylori. Data from the experiments for antibody binding to LPS suggested that the polysaccharide chains from many H. pylori strains showed high immunogenicity in humans. Sera from most (above 70%) H. pylori-infected individuals contained immunoglobulin G (IgG) antibodies against the polysaccharide region highly immunogenic H. pylori LPS. The IgG titers of individual serum samples that reacted strongly with highly immunogenic LPS were quite similar (r2 = 0.84 to 0.98). The results suggest wide distribution among H. pylori strains of a highly antigenic epitope in the polysaccharide moieties of their LPS. Also, the similarity in the titers of individual serum samples against highly immunogenic LPS points to the existence of epitopes sharing a common structural motif. However, some strains showed low antigenicity, even those with polysaccharide-carrying LPS. The dominant subclass of IgG that reacted with the highly immunogenic LPS was IgG2, which was preferentially raised against polysaccharide antigens. Recently, a structure that mimics that of the Lewis antigens was identified in the O-polysaccharide fraction of H. pylori LPS; however, no correlation between antigenicity of the polysaccharide chain in humans and the presence of Lewis antigens was found. The IgA and IgM titers against H. pylori LPS seemed to be mostly nonspecific and directed against lipid A. In a few cases, however, sera from individuals infected with H. pylori gave strong IgA and IgM titers against the highly immunogenic polysaccharide. In conclusion, the LPS of many H. pylori strains possess an antigenic epitope in their polysaccharide regions that is immunogenic in humans. However, our results show that the antigenic epitope is unlikely to be immunologically related to structures mimicking Lewis antigens.     

Taking the low (stretch) road

Helicobacter pylori infection can be detected by several invasive tests based on gastroscopy and by noninvasive methods such as serologic assays. Noninvasive tests can be used not only in addition to invasive tests but also by themselves to screen for H. pylori infection in patients who are not in urgent need of endoscopy. Lately, rapid qualitative serologic tests have been developed. In the present study, the accuracy of a novel rapid whole-blood test, Pyloriset Screen, detecting immunoglobulin G (IgG) and IgA antibodies against H. pylori was evaluated. A total of 207 consecutive adult outpatients referred for upper endoscopy were enrolled. Gastric biopsy specimens were taken from the antrum and corpus for histologic examination and rapid urease testing. Cultures were available for 113 patients. Serum samples collected from all patients were tested for H. pylori antibodies by two enzyme immunoassays (EIAs) (Pyloriset EIA and an in-house EIA), a rapid latex agglutination test (Pyloriset Dry), and Pyloriset Screen. Patients were considered H. pylori positive if helicobacters were seen on histologic examination (77 patients) or, if in combination with histologically verified (although helicobacter-negative) gastritis, their IgG antibody titers were elevated in the two EIAs (five patients). The Pyloriset Screen test had a sensitivity of 95%, a specificity of 94%, a positive predictive value of 91%, and a negative predictive value of 97%. Among 63 patients under the age of 45 years, the Pyloriset Screen test did not miss a single H. pylori diagnosis, and only 1 patient had a false-positive result. Pyloriset Screen could be used reliably to screen for H. pylori infection.