Two enzyme immunoassays and PCR for detection of Helicobacter pylori in stool specimens from pediatric patients before and after eradication therapy

This study of pediatric patients was intended to determine the suitability of stool PCR and two antigen enzyme immunoassays (EIAs; Premier Platinum HpSA and the novel FemtoLab H. pylori), which detect Helicobacter pylori antigens in feces, as pretreatment diagnostic tools and especially as posttreatment control. Forty-nine H. pylori-infected children with dyspepsia received eradication therapy. Successful treatment was determined by a negative [(13)C]urea breath test 4 and 12 weeks after discontinuation of therapy. Fecal specimens were collected prior to eradication therapy as well as 4 weeks after the end of treatment. Successfully treated children delivered stool samples at 6, 8, and 12 weeks posttreatment also. Specimens were examined by seminested PCR and Premier Platinum HpSA and were reexamined by both EIAs as soon as FemtoLab H. pylori was available. In the first test series, the overall sensitivities of PCR and Premier Platinum HpSA were 93.0 and 91.1%, respectively. With specimens collected at 4 weeks after treatment, the respective specificities were 68.8 and 79.3%. After longer follow-up periods, however, they gradually increased to 100 and 96.9%, respectively. In the new test series, Premier Platinum HpSA delivered a considerably lower number of false-positive results (4 versus 18), indicating intertest variations. The overall test sensitivity was 94.6%, and the overall specificity was 97.5%. FemtoLab H. pylori showed an excellent performance with an overall sensitivity and specificity of 98.2 and 98.1%, respectively. Thus, in contrast to PCR, both EIAs were shown to be suitable for early posttreatment control.     

Non-invasive techniques for the diagnosis of Helicobacter pylori infection

Helicobacter pylori infection can be diagnosed by invasive techniques requiring endoscopy and biopsy (histologic examination, culture, polymerase chain reaction), and non-invasive techniques (serology, urea breath test, urine or blood, detection of H. pylori antigen in stool specimen). However, recent studies have demonstrated that a strategy of 'testing and treating' for H. pylori in uninvestigated, young (<50 years), dyspeptic patients in primary care is safe and reduces the need for endoscopy. Indeed, a number of clinical guidelines recommend non-invasive testing in dyspeptic patients followed by treatment of H. pylori in primary care based on clinical and economic analyses. Several non-invasive tests are currently available on the market. The choice depends on the clinical circumstances, the likelihood ratio of positive and negative tests, the cost-effectiveness of the testing strategy, and, finally, the availability of the tests. Nevertheless, two non-invasive tests are commonly used: the urea breath test, and the stool antigen test.     

The Utility of the helicobacter pylori stool antigen test in managing dyspepsia: an experience from a low resource setting

Background

Dyspepsia is defined as a chronic or recurrent pain or discomfort centered in the upper abdomen. Endoscopy is the best strategy for confirming the cause of dyspepsia. Non- invasive strategies would be more appropriate in low resource countries where endoscopy is not readily available. However, there is concern that these strategies may miss serious disease like gastric cancer. One test that needs to be assessed in this regard is the Helicobacter pylori stool antigen test (HPSAT).

Objective

To determine the validity of the stool antigen test in predicting H. pylori associated disease among patients with dyspepsia.

Methods

In this prospective study patients with dyspepsia attending Mulago Hospital were recruited consecutively. Helicobacter pylori was determined using the Rapid Strip HpSA ®, endoscopy and gastric mucosal biopsy were done.

Results

167 patients with dyspepsia were recruited into the study. There were ninety six (57.5%) females and seventy one (42.5%) males with an average age of 48.1(±18.1) years. Patients presenting with dyspepsia in Mulago hospital were more likely to come from the Central 60 (36%) and western tribes 55 (33%). The commonest endoscopic finding was oesophagitis 25 (15%). Peptic ulcer disease was found in 32 (19.2%) and 54 (32.3%) had normal endoscopy findings. H pylori was found in 33.5% and 32.5% using the HPSAT and histology respectively. The validity of the HPSAT in predicting H.pylori associated diseases was generally low with an overall sensitivity of 55.8%, and specificity of 74.2%. However, the validity was higher in predicting the diagnosis of peptic ulcer disease with a sensitivity 59.4% and specificity 72.6%.

Conclusion and recommendations

The HPSAT may be used in the test and treat strategy for young patients with dyspepsia without alarm signs and symptoms in low resource settings. However, because of its low validity in predicting H.pylori associated disease, it is important to follow up patients so that if symptoms persist or recur endoscopy is performed     

Evaluation of the novel Helicobacter pylori ClariRes real-time PCR assay for detection and clarithromycin susceptibility testing of H. pylori in stool specimens from symptomatic children

The aim of the present study was to evaluate the Helicobacter pylori ClariRes assay (Ingenetix, Vienna, Austria) for the detection of H. pylori infection and the simultaneous clarithromycin susceptibility testing of the H. pylori isolates in stool samples from 100 symptomatic children. The results obtained by this novel biprobe real-time PCR method were directly compared with the results obtained from histological examination of gastric biopsy specimens, culturing, the [13C]urea breath test, and a monoclonal antibody-based stool antigen enzyme immunoassay (EIA). Fecal specimens from all 54 children who were shown to be noninfected by "gold standard" tests gave true-negative PCR results (specificity, 100%). Of the remaining 46 individuals with a positive H. pylori status, 29 were found to be positive by real-time PCR (sensitivity, 63%). For these 29 cases, the H. pylori ClariRes assay confirmed all results from phenotypic clarithromycin susceptibility testing by Etest. In summary, this investigation demonstrates that detection of Helicobacter DNA in stool samples by real-time PCR is a difficult task and that this method cannot replace the stool antigen EIA (sensitivity, 95.7%) for the accurate diagnosis of H. pylori infection in children.     

Evaluation of the Helicobacter pylori stool antigen (HpSA) test in routine clinical practice--is it patient-friendly?

A new immunoassay has been developed to detect the presence of Helicobacter pylori antigens in stool specimens. The aim of our study was to assess the accuracy and utility of the H. pylori stool antigen (HpSA) test in routine clinical practice. Dyspeptic patients undergoing endoscopy were studied. H. pylori status was defined before treatment by CLOtest and histology, and by 13C urea breath test (UBT) after eradication therapy. A standard universal container was provided for stool collection and the HpSA test was performed by an investigator blind to the results of the other diagnostic tests. Patients also provided a venous blood sample prior to endoscopy for H. pylori serology. Sixty patients (30 M : 30 F: mean age 47 yr) were enrolled in the study. The pretreatment sensitivity, specificity, positive and negative predictive value of the HpSA test were respectively, 93%, 94%, 96%, and 90%. Twenty five patients returned for post treatment 13CUBT, but only 14 (56%) provided a stool sample for analysis. The post treatment sensitivity, specificity, positive and negative predictive value of the HpSA test were respectively, 67%, 100%, 67%, and 92%. The HpSA test was negative in 19% of the patients found positive for anti-H. pylori antibodies on serology testing. All H. pylori antibody-negative patients had a negative HpSA test. Our results suggest that the HpSA test provides accurate pretreatment diagnosis of H. pylori infection but the reliability of the test after treatment is uncertain. A potential problem with the HpSA test appears to be patient reluctance about stool handling and this could prove a significant obstacle to patient compliance and the acceptability of the test in everyday clinical practice.     

Detection of Helicobacter pylori antigen in stool by enzyme immunoassay

Invasive techniques for diagnosis of Helicobacter pylori (H. pylori) infection require an endoscopic examination which is expensive and inconvenient and may cause complications. Stool cultures for H. pylori or a direct detection of H. pylori antigen in stools by PCR are expensive, tedious, and have a low sensitivity. We recently used an enzyme immunoassay (EIA) to detect H. pylori antigen in stool specimens. A total of 41 patients were seen at Inha University Hospital, Inchon, Korea between September and October 1998. There were 26 men and 15 women who had an average age of 37.6 years which ranged from 5 to 71 years in the present study. All of these patients came to the hospital complaining of an upper abdominal discomfort and were subjected to endoscopy and biopsies. Fifteen had a gastric ulcer, 13 had a duodenal ulcer, 1 had an early gastric cancer, and there were 12 chronic gastritis patients as shown by endoscopy. The biopsy specimens were examined by histology, CLO test, and cultures and these results were used as gold standards. Stool specimens were tested for the H. pylori antigen by EIA. A dual wavelength cut-off of 0.100 that was recommended by the manufacturer gave a good performance (87.1% sensitivity, 100% specificity, 100% positive predictive value, 71.4% negative predictive value, and a 90.2% efficiency). But the adjusted cut-off value using the receiver operating characteristic curve improved the performance of the test (using the cut-off value of 0.024, the sensitivity, specificity, PPV, NPV, and efficiency were 100%, 90.0%, 96.9%, 100%, and 97.6% respectively). Re-evaluation of the cut-off value may be needed for Korean patients. This technique is non-invasive, rapid, easy-to-use, and shows good performance characteristics for diagnosis of H. pylori infections. Therefore, this technique may be a substitute for gastric endoscopy especially in children and some patients who are unable to tolerate an endoscopic examination and it may be substituted for a serologic test in epidemiological research.     

Limited impact on endoscopy demand from a primary care based ‘test and treat’ dyspepsia management strategy: the results of a randomised controlled trial

BACKGROUND: Helicobacter pylori testing has been suggested as an alternative to endoscopy for young patients with dyspepsia. Secondary care studies have suggested that demand for endoscopy among this group could be reduced by up to 74%. However, the effect of H. pylori testing in the primary care setting, where the majority of dyspepsia is managed, is unclear. AIM: To determine the effects of providing a H. pylori serology service for GPs upon demand for open access endoscopy. DESIGN OF STUDY: A prospective randomised controlled trial. SETTING: Forty-seven general practices in Gloucestershire. METHOD: General practices were stratified by endoscopy referral rate and randomised into two groups. The intervention group was provided with access to H. pylori serology testing and encouraged to use it in place of endoscopy for patients aged under 55 years with dyspepsia. Endpoints were referral for endoscopy and serology use. RESULTS: There was a significant reduction in referrals for endoscopy in the intervention group compared to the control group: 18.8% (95% confidence interval = 5.0 to 30.6%; P = 0.009). CONCLUSIONS: Providing GPs with H. pylori serology testing reduced demand for open access endoscopy, but by less than previous studies had predicted.     

幽门螺杆菌粪便抗原检测方法学评价

目的 评价幽门螺杆菌粪便抗原（ HpSA）检测在诊断患者幽门螺杆菌（Hp）感染中的价值.方法 以胃镜病理学诊断结果为金标准,对328例有消化道症状患者粪便,同时应用酶联免疫吸附实验检测幽门螺杆菌粪便抗原,计算HpSA检测诊断Hp感染的特异性、灵敏度和准确性等性能指标.结果 幽门杆菌粪便抗原酶免疫检测法对Hp感染诊断与金标准相比无统计学差异（P＞0.05）,其敏感性为94.6％、特异性为96.9％、准确性为96.3％、阳性预期值为89.7％、阴性预期值为98.4％.结论 幽门螺杆菌粪便抗原酶免疫检测是一种简便、易行、准确性高、便宜、易重复的非侵入性检测方法.     

Novel real-time PCR assay for detection of Helicobacter pylori infection and simultaneous clarithromycin susceptibility testing of stool and biopsy specimens

A biprobe real-time PCR protocol, followed by hybridization melting point analysis, to detect point mutations in the 23S rRNA gene of Helicobacter pylori associated with clarithromycin resistance was established and evaluated in a clinical study. Of 92 patients who underwent endoscopy, 45 were found to be H. pylori infected and invariably were also culture positive. Of the 45 isolates, 11 were shown to be resistant to clarithromycin by E-test. With respect to the detection of H. pylori infection, PCR showed sensitivities of 100% in biopsies and 98% in stool specimens and a specificity of 98% in both biopsy and stool samples. All clarithromycin-sensitive cases were identified as such by PCR in both biopsy and stool samples. Of the cases with a resistant strain, eight were identified as such in stool DNA and nine were identified in biopsy DNA. Failure of PCR to detect the resistant genotype in the biopsy DNA, stool DNA, or both (one case) was associated with mixed populations. In these cases, patients had not been treated for H. pylori infection before, and the sensitive population showed to be present in considerably higher numbers than the resistant population. In five of six cases in which infection with a resistant genotype only was identified by PCR, the patients had received clarithromycin-based eradication therapy in the past. Thus, the assay presented provides a highly accurate noninvasive method to detect H. pylori infection in stool and at the same time allows for culture-independent clarithromycin susceptibility testing.     

Histology compared with chemical testing for urease for rapid detection of Helicobacter pylori in gastric biopsy specimens.

Gastric biopsy specimens from 283 patients with ulcer and non-ulcer dyspepsia attending five gastroenterology clinics in the northern region of the United Arab Emirates (UAE) were tested by the agar gel test (n = 115) or the ultra-rapid endoscopy room test (n = 168) for the presence of Helicobacter pylori urease. Results were compared with a histological technique using the Romanowsky type (Diff-3) stain for detecting H pylori in both antral and body type gastric mucosa. A sensitivity of 94% and specificity of 100% using the agar gel test compared with 87% sensitivity and 99.3% specificity for the ultra-rapid endoscopy room test. Grading of H pylori in gastric biopsy specimens showed that the higher the histological grade, the more likely that the urease test would be positive. Both forms of urease tests have high specificity for detecting H pylori in gastric biopsy specimens, although the urea agar test has a higher sensitivity than the ultra-rapid test. Low numbers of H pylori in gastric biopsy specimens are the most important determinant of a false negative urease test.     

Posttreatment follow-up of Helicobacter pylori infection using a stool antigen immunoassay.

The Helicobacter pylori stool antigen enzyme immunoassay (HpSA) was evaluated during posttreatment follow-up of patients in a country with a very high prevalence of H. pylori infection. From among 273 dyspeptic individuals (18 to 55 years) initially recruited from a shantytown in Lima, Peru, 238 participants who met the inclusion criteria and were suspected to be H. pylori positive based on (14)C urea breath test (UBT) results underwent endoscopy. Participants with endoscopy-proven infections received standard eradication therapy and were monitored by UBT and HpSA at 1 month following treatment and at 3-month intervals for 9 months posttreatment. A second endoscopy was performed if UBT results showed evidence of treatment failure or H. pylori recurrence. Biopsy results were considered the "gold standard" in all analyses. Among patients who underwent endoscopy, HpSA had a pretreatment sensitivity of 93%. Two-hundred thirty patients completed the treatment regimen, of whom 201 (93%) were considered to have had successful treatment outcomes based on a negative follow-up UBT. Thirty-two patients with UBT-defined treatment failures or H. pylori recurrences at any point during the 9-month follow-up underwent a second endoscopy. In the posttreatment setting, HpSA had an overall sensitivity of 73% and a specificity of 67%. Agreement between UBT and HpSA diminished throughout the follow-up. Among 14 participants in whom HpSA remained positive at 1 month following treatment despite UBT evidence of treatment success, 12 (86%) became HpSA negative within 3 months posttreatment. Although this study confirmed the validity of the HpSA in the initial assessment of dyspeptic patients, the test demonstrated a reduced overall accuracy in the detection of treatment failures and H. pylori recurrences during 9 months of posttreatment follow-up. Furthermore, in some patients it may take up to 3 months after successful eradication for antigen shedding to diminish to levels within the negative HpSA range.     

Histology of chronic gastritis with and without duodenitis in patients with Helicobacter pylori infection.

AIM: To compare the histological characteristics of Helicobacter pylori positive chronic gastritis in patients with and without associated duodenitis. METHODS: Gastric mucosal biopsy specimens were obtained from patients undergoing endoscopy for dyspepsia. Severity of gastritis and density of H pylori infection were graded according to the Sydney system. RESULTS: Of the 69 patients studied, 15 had normal histology, 22 had chronic gastritis only (77.3% H pylori positive), 21 had duodenitis (90.5% H pylori positive), and 11 had other diagnoses. In the H pylori positive patients, the median gastritis score was higher in the duodenitis group (6, range 3-9) than in the chronic gastritis only group (5, range 2-8), because of greater neutrophil activity scores in patients with duodenitis (median score 2 v 1). There were no differences in the density of H pylori infection, inflammation, atrophy, or intestinal metaplasia between patients with chronic gastritis only and those with duodenitis. CONCLUSIONS: These results suggest that H pylori positive patients with duodenitis have a more severe form of gastritis than those without associated duodenal inflammation. This is because of increased neutrophil activity, which seems to be independent of the density of H pylori infection.     

Detection of Helicobacter pylori antigen in faeces by enzyme immunoassay

The detection of Helicobacter pylori antigen directly in faecal specimens may offer an alternative non-invasive method for determining the presence of H. pylori infection. This study compared the performance of the Premier Platinum HpSA enzyme immunoassay (HpSA) with histology and CLOtest, a rapid urease test. Of 134 patients undergoing upper gastrointestinal endoscopy, 37 (28%) were H. pylori-positive by histology and CLOtest. Using the HpSA test, H. pylori was detected in 35 H. pylori-positive patients (95% sensitivity) and one H. pylori-negative patient (99% specificity). The positive and negative predictive values for HpSA were 97 and 98%, respectively. HpSA is a rapid, easily performed, non-invasive method for detecting H. pylori.     

Helicobacter pylori infection and the development of gastric cancer

BACKGROUND: Although many studies have found an association between Helicobacter pylori infection and the development of gastric cancer, many aspects of this relation remain uncertain. METHODS: We prospectively studied 1526 Japanese patients who had duodenal ulcers, gastric ulcers, gastric hyperplasia, or nonulcer dyspepsia at the time of enrollment; 1246 had H. pylori infection and 280 did not. The mean follow-up was 7.8 years (range, 1.0 to 10.6). Patients underwent endoscopy with biopsy at enrollment and then between one and three years after enrollment. H. pylori infection was assessed by histologic examination, serologic testing, and rapid urease tests and was defined by a positive result on any of these tests. RESULTS: Gastric cancers developed in 36 (2.9 percent) of the infected and none of the uninfected patients. There were 23 intestinal-type and 13 diffuse-type cancers. Among the patients with H. pylori infection, those with severe gastric atrophy, corpus-predominant gastritis, and intestinal metaplasia were at significantly higher risk for gastric cancer. We detected gastric cancers in 21 (4.7 percent) of the 445 patients with nonulcer dyspepsia, 10 (3.4 percent) of the 297 with gastric ulcers, 5 (2.2 percent) of the 229 with gastric hyperplastic polyps, and none of the 275 with duodenal ulcers. CONCLUSIONS: Gastric cancer develops in persons infected with H. pylori but not in uninfected persons. Those with histologic findings of severe gastric atrophy, corpus-predominant gastritis, or intestinal metaplasia are at increased risk. Persons with H. pylori infection and nonulcer dyspepsia, gastric ulcers, or gastric hyperplastic polyps are also at risk, but those with duodenal ulcers are not.     

Increased gastric production of interleukin-8 and tumour necrosis factor in patients with Helicobacter pylori infection.

AIMS--To investigate the role of interleukin-8 (IL-8) and tumour necrosis factor (TNF) in patients infected with Helicobacter pylori. METHODS--The study population comprised 52 patients with dyspepsia attending for upper gastrointestinal endoscopy. Of these patients, 35 were infected with H pylori. IL-8 and TNF concentrations in plasma, gastric juice, and gastric biopsy homogenate supernatant fluid were measured by radioimmunoassay and L929 cell bioassay, respectively. RESULTS--The concentrations of IL-8 and TNF in gastric juice and gastric biopsy homogenates were substantially greater in patients infected with H pylori. In H pylori positive patients IL-8 concentrations in gastric juice and gastric biopsy homogenates were higher in those with moderate gastritis than in those with mild gastritis. There was a positive correlation between IL-8 and TNF concentrations in gastric juice and gastric biopsy homogenate supernatant fluid from H pylori positive patients. There were no significant differences between H pylori positive and negative patients with respect to IL-8 and TNF plasma concentrations. CONCLUSION--This study suggests that increased gastric production of IL-8 and TNF may be implicated in the pathogenesis of H pylori associated gastroduodenal disease.     

Diagnosis of Helicobacter pylori infection in a colony of rhesus monkeys (Macaca mulatta).

Twenty-three young adult rhesus monkeys from China were evaluated for the presence of Helicobacter pylori. Gastric body and antral biopsy samples were tested for H. pylori by PCR analysis, culture, rapid urease testing, and histologic evaluation. Serologic testing to detect H. pylori immunoglobulin G (IgG) antibodies was performed by using a commercially available human-based enzyme-linked immunosorbent assay (ELISA) test and an ELISA test which utilized homologous H. pylori antigens and an anti-rhesus IgG conjugate. PCR analysis with H. pylori-specific 26-kDa protein primers detected H. pylori in 21 of the 23 rhesus monkeys (91%). Culture testing identified the organism in 12 of the 23 animals (52%). Rapid urease tests were positive for all animals. H. pylori was diagnosed by histological examination in 11 of 23 monkeys (48%). Of the 21 monkeys positive for H. pylori by PCR, only 3 (14%) had positive results by the commercial ELISA test, yielding a sensitivity of 14%, a specificity of 100%, and an accuracy of 22%. However, 19 of the 21 PCR-positive animals (90%) had positive results by the ELISA test with homologous rhesus H. pylori antigen and anti-monkey conjugate, with predicted index values greater than or equal to 0.7 considered positive and values between 0.5 and 0.7 considered equivocal. This test had a sensitivity of 90%, a specificity of 100%, and an accuracy of 91%. Therefore, the ELISA test with rhesus monkey origin components was more accurate for detecting infected animals than the human-based ELISA.     

Comparison of PCR and other diagnostic techniques for detection of Helicobacter pylori infection in dyspeptic patients.

A sensitive and specific PCR-based assay to detect the Helicobacter pylori 16S rRNA gene present in formalin-fixed paraffin-embedded gastric biopsy specimens has been developed. A total of 95 patients with dyspepsia were evaluated for the presence of chronic active gastritis and an infection with H. pylori through the use of diagnostic assays based on biopsy specimens and serology. The "gold standard" for the presence of the bacteria was direct detection in histological sections of biopsy specimens by Giemsa stain. The results obtained with the PCR assay performed on the biopsy specimens (94% sensitivity and 100% specificity) were equivalent to the detection of H. pylori immunoglobulin G antibodies by the commercially available second-generation Cobas Core anti-H. pylori immunoglobulin G enzyme immunoassay (94% sensitivity and 98% specificity) for the diagnosis of H. pylori infection. Urease testing and bacterial culture of the biopsy specimens were inferior (88 and 70% sensitivity and 96% and 98% specificity, respectively). A Western blot (immunoblot) analysis had slightly greater sensitivity (96%), although specificity was reduced to 93%. This research prototype PCR assay was shown to be highly reliable for the detection of infection with H. pylori and the presence of chronic active gastritis in the population studied.     

Chronic inactive gastritis and coccoid Helicobacter pylori in patients treated for gastroesophageal reflux disease or with H pylori eradication therapy

Gastric biopsy specimens from 105 consecutive adults with persistent dyspepsia who did not have changes due to esophageal reflux disease changes or gastric or duodenal ulcers at endoscopy were scored using the updated Sydney gastritis classification system. The medication history of proton pump inhibitors (PPIs) or Helicobacter pylori eradication therapy during the month before endoscopy was retrieved. Of the patients, 72 (68.6%) had chronic inactive gastritis, and 7 (6.7%) had antral-predominant, chronic mild active gastritis. H pylori infection was present in 36 patients (34.3%), of whom 29 had chronic inactive gastritis. Forty-six patients (43.8%) had a positive medication history, including 40 (56%) of 72 with chronic inactive gastritis. The most common morphologic feature associated with H pylori infection was moderate chronic inactive gastritis, which was found most often in patients who had received recent PPIs or H pylori eradication therapy. Pathologists should be aware of the extensive use of these medications, their association with chronic inactive gastritis, and rare H pylori thatfrequently are coccoid shaped. Modified Giemsa stain may not be the optimal method to detect H pylori in this group of patients.     

Accuracy of serology for the diagnosis of Helicobacter pylori infection--a comparison of eight kits.

AIMS: To determine the accuracy of eight commercially available kits for the serological diagnosis of Helicobacter pylori infection, and hence whether a serology service could be introduced to reduce endoscopy workload. METHODS: Eighty four patients newly presenting to their general practitioners with dyspepsia were recruited. Gold standard diagnosis of H pylori infection was obtained both by a histological examination of gastroduodenal biopsy specimens and by the 14C-urea breath test (UBT). The performance of six quantitative and two qualitative enzyme linked immunosorbent assays for H pylori IgG, used according to the manufacturers' instructions, with serum samples obtained during the endoscopy visit, were compared. RESULTS: The study population had a median age of 45 years, and the prevalence of H pylori infection was 35%. With one exception, where the patient had received a course of anti-H pylori treatment between endoscopy and UBT, there was 100% concordance in the results of the two gold standard techniques. Discordant serology results were more common in patients aged > 50 years (42% of the total) than in younger patients (21%), and this was most noticeable in uninfected patients. The sensitivity of the kits was good (90-100%), but specificity was more variable (76-96%), and the rate of equivocal results was unacceptably high in some cases (0-12%). The overall accuracy of the kits ranged from 83 to 98%. Two kits in particular performed well (Pylori-Elisa II, Bio-Whitaker and Premier, Launch; qualitative) with 98% and 100% accuracy, respectively. CONCLUSIONS: In a symptomatic population with a prevalence of H pylori infection of 35%, particularly in patients aged < 50 years, some but not all serology kits may be used as a highly accurate and inexpensive alternative to the gold standard techniques.     

Detection of Helicobacter pylori gastritis by PCR: correlation with inflammation scores and immunohistochemical and CLOtest findings

We developed a polymerase chain reaction (PCR) assay to detect Helicobacter pylori in gastric and/or gastroesophageal biopsy specimens of adults with dyspepsia, compared the method with immunohistochemical analysis and CLOtest (Ballard Medical Products, Draper, UT), and correlated the results of each test with the histologic features of infection. H pylori was identified in 36 (60%) of 60 patients irrespective of biopsy site and testing method. In the gastric biopsy specimens, PCR detected H pylori in 29 (52%) of 56 cases, including 11 (100%) of 11 immunohistochemically and/or CLOtest-positive cases. PCR-positive gastric biopsy specimens correlated with a higher average cumulative inflammatory score compared with PCR-negative specimens (P = .001). In gastroesophageal biopsy specimens, PCR detected H pylori in 15 (34%) of 44 cases, including 1 (20%) of 5 immunohistochemically positive specimens. PCR-positive gastroesophageal junction biopsy specimens did not correlate with a higher average cumulative inflammatory score. Overall, PCR detected an additional 23 cases negative by immunohistochemical analysis and/or CLOtest. This PCR assay identified a significant number of H pylori infections that would not be detected by immunohistochemical analysis and/or CLOtest.