Effect of blood on rapid urease testing of gastric mucosal biopsy specimens

Diagnosis, treatment, and outcome in patients with bleeding peptic ulcers and Helicobacter pylori infections

Upper gastrointestinal (UGI) bleeding is the most frequently encountered complication of peptic ulcer disease. Helicobacter pylori (Hp) infection and nonsteroidal anti-inflammatory drug (NSAID) administration are two independent risk factors for UGI bleeding. Therefore, testing for and diagnosing Hp infection are essential for every patient with UGI hemorrhage. The presence of the infection is usually underestimated in cases of bleeding peptic ulcers. A rapid urease test (RUT), with or without histology, is usually the first test performed during endoscopy. If the initial diagnostic test is negative, a delayed ¹³C-urea breath test (UBT) or serology should be performed. Once an infection is diagnosed, antibiotic treatment is advocated. Sufficient evidence supports the concept that Hp infection eradication can heal the ulcer and reduce the likelihood of rebleeding. With increased awareness of the effects of Hp infection, the etiologies of bleeding peptic ulcers have shifted to NSAID use, old age, and disease comorbidity.

Endoscopic diagnosis of Helicobacter pylori infection by rapid urease test in bleeding peptic ulcers: a prospective case-control study

GOAL

To assess the efficacy of rapid urease test (RUT) in patients with bleeding ulcers, as well as the effects of visible blood in the stomach and short-term (<24 h) use of standard-dose proton pump inhibitor (PPI) on RUT sensitivity.

BACKGROUND

The sensitivity of RUT in the diagnosis of Helicobacter pylori in upper gastrointestinal bleeding has been reported with conflicting results.

STUDY

This was a prospective case-control study evaluating 324 consecutive patients with bleeding peptic ulcers (study group) and 164 with uncomplicated ulcers (control group). The presence of H. pylori infection was determined by both RUT and histology. Prevalence of H. pylori infection and the RUT sensitivity in diagnosing the bacteria between study and control groups were conducted.

RESULTS

The prevalence of H. pylori infection in those with bleeding ulcers was significantly lower than that of controls (53.7% vs. 65.2%, P=0.015). The false-negative rate of RUT in the study group was significantly greater than that of the control group (16.7% vs. 5.6%, P=0.006), whereas the sensitivity rates in the study group with or without gastric blood were significantly lower than those of the controls (79.6% vs. 94.4%, P=0.005; 84.8% vs. 94.4%, P=0.019). There was no significant difference in RUT sensitivity between study group with or without visible gastric blood (P=0.41). The RUT sensitivity rate was also not significantly different between those treated with PPI and those without in patients with bleeding ulcers (82.7% vs. 85.7%, P=0.67).

CONCLUSIONS

This study shows that the sensitivity of RUT in patients with bleeding ulcers is reduced. The presence of blood in the stomach and the short-term use of standard-dose PPI do not affect the RUT sensitivity in bleeding ulcers.

Outcomes of bleeding peptic ulcers: a prospective study

BACKGROUND AND AIM

Bleeding peptic ulcers can be due to Helicobacter pylori (H. pylori) infection, use of non-steroidal anti-inflammatory drugs (NSAIDs), or idiopathic causes. The aim of this prospective study was to identify the clinical outcomes of bleeding peptic ulcers related to different causes.

METHODS

A total of 390 patients with bleeding ulcers were evaluated consecutively between June 2005 and August 2006. The diagnosis of H. pylori infection was made at index endoscopy, using histology and the rapid urease test. If both endoscopic diagnostic tests were not performed, a serological test was applied to detect the presence of H. pylori infection in a previously untreated patient. The prevalence and outcome of bleeding ulcers are related to H. pylori infection, NSAID use, and non-H. pylori idiopathic causes. The outcome between patients who were admitted for ulcer bleeding (outpatient bleeder) and those who bled while hospitalized (in-hospital bleeder) was also compared.

RESULTS

NSAID ulcers were noted in 223 patients, H. pylori ulcers in 102, and non-H. pylori idiopathic ulcers in 65. In total, 298 patients had outpatient bleeders, and 92 had in-hospital bleeders. The overall 3-day rebleeding rate was 11.8% and the mortality rate was 5.4%. Eighteen of the 21 mortality cases died of their underlying comorbid illness. Patients with non-H. pylori idiopathic ulcers had a significantly higher mortality rate than NSAID and H. pylori ulcers (12.3% vs 4.5% vs 2.9%, P = 0.02). Patients with H. pylori ulcers had significantly favorable outcomes than patients with NSAID ulcers (less blood transfusion and a shorter hospital stay) and non-H. pylori idiopathic ulcers (shorter hospital stay and a lower mortality). Patients with in-hospital bleeders had an adverse outcome as compared to outpatient bleeders, including a 3-day rebleeding rate (25.0% vs 7.7%, P < 0.0001), 30-day rebleeding rate (32.6% vs 12.1%, P < 0.0001), and higher mortality rate (16.3% vs 2.0%, P < 0.0001).

CONCLUSION

This study emphasizes the role of non-H. pylori idiopathic ulcers and in-hospital bleeders as the determining high-risk predictors for bleeding peptic ulcers.

Accuracy of Helicobacter pylori diagnostic tests in patients with bleeding peptic ulcer: a systematic review and meta-analysis

OBJECTIVE

To perform a systematic review and a meta-analysis of diagnostic accuracy of the different tests aimed to detect Helicobacter pylori infection in patients with upper gastrointestinal bleeding (UGIB).

SELECTION OF STUDIES

assessing the accuracy of H. pylori diagnostic methods in patients with UGIB.

SEARCH STRATEGY

electronic bibliographical searches.

DATA EXTRACTION

independently done by two reviewers.

DATA SYNTHESIS

meta-analyses of the different tests were performed combining the sensitivities, specificities, and likelihood ratios (LRs) of the individual studies.

RESULTS

Studies showed a high degree of heterogeneity. Pooled sensitivity, specificity, LR+ and LR- (95% confidence interval (CI)) for the different methods were: Rapid urease test (16 studies/1,417 patients): 0.67 (0.64-0.70), 0.93 (0.90-0.96), 9.6 (5.1-18.1), and 0.31 (0.22-0.44). Histology (10 studies/827 patients): 0.70 (0.66-0.74), 0.90 (0.85-0.94), 6.7 (2.5-18.4), and 0.23 (0.12-0.46). Culture (3 studies/314 patients): 0.45 (0.39-0.51), 0.98 (0.92-1.00), 19.6 (4-96), and 0.31 (0.05-1.9). Urea breath test (8 studies/520 patients): 0.93 (0.90-0.95), 0.92 (0.87-0.96), 9.5 (3.9-23.3), and 0.11 (0.07-0.16). Stool antigen test (6 studies/377 patients): 0.87 (0.82-0.91), 0.70 (0.62-0.78), 2.3 (1.4-4), and 0.2 (0.13-0.3). Serology (9 studies/803 patients): 0.88 (0.85-0.90), 0.69 (0.62-0.75), 2.5 (1.6-4.1), and 0.25 (0.19-0.33).

CONCLUSION

Biopsy-based methods, such as rapid urease test, histology, and culture, have a low sensitivity, but a high specificity, in patients with UGIB. The accuracy of 13C-urea breath test remains very high in these patients. Stool antigen test is less accurate in UGIB. Although serology seems not to be influenced by UGIB, it cannot be recommended as the first diagnostic test for H. pylori infection in this setting.

The effect of GI bleeding on Helicobacter pylori diagnostic testing: a prospective study at the time of bleeding and 1 month later

BACKGROUND

Some case series and cohort studies suggest that acute GI bleeding decreases the sensitivity of Helicobacter pylori diagnostic testing.

OBJECTIVE

To assess H pylori biopsy testing in patients with acute upper-GI bleeding and 1 month later.

DESIGN

Prospective cohort study using patients as their own controls.

SETTING

Urban county hospital.

PATIENTS

Sixty-one patients with acute variceal bleeding.

INTERVENTIONS

Antral and body endoscopic biopsies at admission and 1 month later.

MAIN OUTCOME MEASUREMENTS

CLOtest and histologic examinations were performed and biopsy specimens were coded and mixed for blinded histologic examination for H pylori density and inflammation.

RESULTS

CLOtest results changed from H pylori negative at baseline to H pylori positive at 1 month in two patients (3%), from H pylori positive to H pylori negative in 6 patients (10%), and remained the same in 53 (87%). Histologic results changed from H pylori negative at baseline to H pylori positive at 1 month in two patients (3%), from H pylori positive to H pylori negative in 5 patients (8%), and remained the same in 54 (89%). Changes occurred only in patients with low H pylori density. No significant increase in H pylori density or change in inflammatory cell infiltration was seen. CLOtest sensitivity was 8% higher with bleeding vs. 1 month after bleeding (79% vs. 71%; 95% CI of difference was -11% to 27%; i.e., maximal potential decrease in sensitivity with bleeding is 11%).

LIMITATIONS

The population is not one for which H pylori testing is recommended, and biopsy test performance was less consistent than expected.

CONCLUSIONS

Acute-GI bleeding did not decrease the sensitivity of rapid urease testing, unless the effect lasts more than 1 month. Furthermore, bleeding did not produce falsely negative histologic examinations for H pylori, decrease H pylori density, or alter inflammatory cell infiltration. However, given the lower than expected overall CLOtest sensitivity and frequent use of proton pump inhibitors for GI bleeding, histology may be preferred in this setting.

Evaluation of a new biopsy urease test: Pronto Dry, for the diagnosis of Helicobacter pylori infection

BACKGROUND

The gastric biopsy urease test is the most frequently used test for the diagnosis of Helicobacter pylori infection in routine gastrointestinal endoscopy practice. In Malaysia up to recently, only one commercial biopsy urease test was available: the CLO test (Ballard Medical Products, Draper, Utah, USA). Large endoscopy units use their own 'homemade' unbuffered ultra rapid urease test for diagnosis of H. pylori infection.

OBJECTIVE

To compare the accuracy and reaction time of a new biopsy urease test, Pronto Dry (Medical Instruments Corporation, Solothurn, Switzerland) and the CLO test in the diagnosis of H. pylori infection.

METHODS

Consecutive patients presenting with dyspepsia to the endoscopy unit, University of Malaya Medical Centre were recruited for the study. Patients who were previously treated for H. pylori infection or who had received antibiotics, proton pump inhibitors or bismuth compounds in the preceding 4 weeks were excluded. H. pylori diagnosis was made based on the ultra rapid urease test and histological examination of gastric biopsies. Four antral and four corpus biopsies were taken for this purpose from all patients. A diagnosis of H. pylori infection was made when both the ultra rapid urease test and histology were positive in either the antral or corpus biopsies. A negative diagnosis of H. pylori was made when both tests from antral and corpus biopsies were all negative. Another four antral and four corpus biopsies (two each) were taken for the Pronto Dry and CLO tests. The Pronto Dry and CLO tests were stored and performed according to the manufacturer's instruction.

RESULTS

Two hundred and eight patients were recruited in the study. Eighty-six of the patients were males and 122 were females. The mean age was 46.3 years with a range of 15-82 years. The results for both the Pronto Dry and the CLO tests were completely concordant with sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of 98.1%, 100%, 100%, 98.1% and 99%, respectively. The Pronto Dry test showed a faster reaction time to positive compared with the CLO test, with 96.2% positive reaction by 30 min versus 70.8% and 100% positive reaction time by 55 min versus 83%. The colorimetric change was also more distinct with the Pronto Dry test compared with the CLO test.

CONCLUSIONS

Both the Pronto Dry and the CLO tests were highly accurate for the diagnosis of H. pylori infection. The Pronto Dry test showed a quicker positive reaction time and the positive colour change was more distinct.

Changing rates of Helicobacter pylori testing and treatment in patients with peptic ulcer disease

OBJECTIVES

The aim of this study was to identify temporal trends in the rate of Helicobacter pylori (H. pylori) testing, prevalence, and treatment among patients with peptic ulcer disease in Olmsted County, MN, from 1984 through 1997.

METHODS

All 3317 Olmsted County residents with a clinical diagnosis of peptic ulcer disease at the Mayo Clinic from 1984 through 1997 were identified. The complete medical records of an age-, sex-, and calendar year-stratified random sample were reviewed (n = 720); 298 patients (41%) had confirmed peptic ulcer disease. Changes in proportions of H. pylori testing, infection, and treatment over time were analyzed by logistic regression.

RESULTS

Of the 298 patients with confirmed peptic ulcer disease, 32% were tested for H. pylori; 36% were positive for infection, of whom 66% received antibiotic therapy. The rate of testing for H. pylori increased from 0% in 1984 to 96% in 1997, but the prevalence of infection did not change (36.4% vs 36.5%). The rate of treatment of those infected increased from 0% to 95%. By logistic regression, calendar year was associated with H. pylori testing and treatment but not infection. Recent use of nonsteroidal anti-inflammatory drugs was reported by 58% of patients, and 44% presented with GI bleeding.

CONCLUSIONS

Physicians' practice of testing and treating for H. pylori in patients with confirmed peptic ulcer disease has steadily increased over the past 14 yr. However, in our study, only 36% of these patients were infected with H. pylori, whereas the majority used nonsteroidal anti-inflammatory drugs (NSAIDs). Therefore, testing seems to be more appropriate than empiric treatment in patients with peptic ulcer disease.

Human plasma is directly bacteriocidal against Helicobacter pylori in vitro, potentially explaining the decreased detection of Helicobacter pylori during acute upper GI bleeding

BACKGROUND

The rapid urease test is the preferred method for detection of H pylori in patients with uncomplicated ulcer disease undergoing EGD. However, the sensitivity of this test when performed during upper GI bleeding has been questioned. It has been suggested that false-negative results occur, resulting from buffering effects of blood. The direct effect of blood was evaluated on H pylori growth in ex vivo and in vitro systems.

METHODS

Antral biopsy specimens obtained from 100 consecutive patients undergoing EGD were cultured with and without autologous blood, and RUT results at 5, 15, and 30 minutes were compared. In addition, H pylori bacterial cultures of a virulent laboratory strain were incubated with blood or blood components from 5 patients who were H pylori positive and 5 who were H pylori negative. The effect of blood on H pylori growth was determined by rapid urease test and direct bacterial plating with colony-forming unit determination.

RESULTS

Three hundred antral biopsy specimens from 100 patients were divided into 900 fragments for rapid urease test evaluation. There was no statistical difference in rapid urease test results for biopsy fragments tested immediately, cultured in blood, or cultured in phosphate-buffered saline solution. In contrast, in vitro studies demonstrated that whole blood and plasma effectively killed H pylori, whereas neutrophils and mononuclear cells had no detrimental effect on H pylori growth.

CONCLUSION

Human plasma contains factors that kill H pylori in vitro. This may be a possible explanation for the lower-than-expected rapid urease test detection of H pylori during active upper GI bleeding.

Rapid urease test: effect of preimmersion of biopsy forceps in formalin

OBJECTIVE

The rapid urease test is widely used at endoscopy to determine the presence of Helicobacter pylori. The effect of immersion of the biopsy forceps in formalin before performance of a rapid urease test is uncertain. The aim of this prospective study was to determine whether previous immersion of the biopsy forceps in formalin influences rapid urease test results.

METHODS

Two hundred fifty-three consecutive patients undergoing upper GI endoscopy with a clinical indication for rapid urease test had two tests with two different antral mucosa biopsies. The former was performed with a sterile biopsy forceps, the latter with a sterile biopsy forceps that was previously immersed in 10% buffered formalin. In 132 patients the CLOtest was used and in 121 patients the Jatrox-H.P. test was used. The kappa concordance test was used for comparisons.

RESULTS

In the 132 patients in which the CLOtest was used, both were positive in 76 cases, both negative in 27, and discordant results were seen in 3 cases (2.27%), kappa 0.953 (range 0.901-1.000, p < 0.001). In the 121 patients in which the Jatrox test was used, both were positive in 89, both negative in 27 and there were 5 (4.13%) discordant cases, kappa 0.880 (0.793-0.984, p < 0.001). There were no differences in positivity rates at 30 minutes, 1 hour, and 3 hours between the two rapid urease test kits.

CONCLUSION

Preimmersion of the biopsy forceps in formalin does not adversely affect the rapid urease test.

Is non-Helicobacter pylori, non-NSAID peptic ulcer a common cause of upper GI bleeding? A prospective study of 977 patients

BACKGROUND

Non-Helicobacter pylori, non-NSAID ulcer is relatively common in Western countries. Whether it is a significant problem in the Orient is unclear. The aim of this study was to investigate the incidence of non-H pylori, non-NSAID ulcers presenting with GI bleeding.

METHODS

A prospective study was done of 1675 consecutive patients presenting with upper GI bleeding over a period of 12 months. Upper endoscopy was performed with biopsy specimens taken from the antrum and body of the stomach for a biopsy urease test (BUT) and histology for detection of H pylori. Exposure to nonsteroidal anti-inflammatory drugs (NSAID) or aspirin within 4 weeks of hospitalization was carefully scrutinized. A 6-week course of treatment with an H2-receptor antagonist was prescribed for patients who did not use an NSAID and had a negative BUT result. Follow-up endoscopy was performed to confirm H pylori status with a BUT and histology. Positive histology at either initial or follow-up endoscopy was used as the standard for diagnosing H pylori infection.

RESULTS

Among 977 patients who were found to have ulcer bleeding, 434 (44%) had exposure to aspirin or an NSAID. Of the 543 non-NSAID users, 431 (79.4%) had a positive BUT and 112 (20.6%) were BUT negative on initial endoscopy. Eighty-nine of 112 patients who were NSAID negative, BUT negative returned for follow-up endoscopy. Forty-nine of 89 (55.1%) were found to have a positive BUT and positive histology at follow-up endoscopy. Only 40 of 977 (4.1%) patients admitted with ulcer bleeding were confirmed to have non-H pylori, non-NSAID ulcers.

CONCLUSIONS

Non-H pylori, non-NSAID bleeding ulcer is uncommon. A negative BUT is unreliable for exclusion of H pylori infection during the acute phase of ulcer bleeding.

Peptic ulcer and Helicobacter pylori

Although there has been an explosion of data not only since the discovery of H. pylori in 1982, but also since the first comprehensive review of H. pylori in the Gastroenterology Clinics in 1993, much remains to be learned. In 1993, there were many skeptics doubting the importance of H. pylori in ulcer disease. Although this skepticism has dissipated, many ulcer patients infected with H. pylori still do not receive appropriate therapy. This situation possibly relates to the safety, efficacy, and simplicity of prescribing acid-suppressive therapy in contrast to the confusion regarding anti-H. pylori treatment regimens. Among the many continuing unanswered questions regarding the role of H. pylori and PUD are the still enigmatic nature of host, environmental, and H. pylori-related factors that determine outcome. Why do only some infected individuals (and why do more men than women) develop PUD, and what determines whether gastric ulcers or duodenal ulcers develop? What is the explanation for the seasonal variation in ulcer disease? Although PUD is an infectious disease, are other environmental factors critical for the manifestation of ulcers in association with infection? What factors govern the outcome of the combination of H. pylori infection and NSAID use? Has attention been too focused first on the pathophysiology of acid secretion and now on H. pylori? In curing H. pylori in association with PUD, are clinicians going to displace disease northward, substituting erosions, inflammation, and neoplasia (and associated symptoms) in the esophagus and gastroesophageal junction for an ulcer crater (and its associated symptoms) in the duodenum or stomach? The epidemiology of PUD is changing--in more recent reports of ulcer patients, H. pylori and NSAID use are less prevalent than in earlier reports. These questions and comments should not be misinterpreted as advocating a lack of aggressiveness in diagnosis and treatment of H. pylori in the setting of PUD, however. Nevertheless, the pendulum is swinging.

Rapid urease tests lack sensitivity in Helicobacter pylori diagnosis when peptic ulcer disease presents with bleeding

OBJECTIVE

The eradication of Helicobacter pylori (H. pylori) in patients with bleeding peptic ulcer disease (PUD) decreases the rate of ulcer rebleeding. Although all methods for H. pylori diagnosis have been extensively evaluated in uncomplicated PUD the efficacy of the commonly used rapid urease test (RUT) has not been established in patients with bleeding peptic ulcer disease. The aim of this study was to evaluate the efficacy of the RUT (CLOtest) in patients with bleeding duodenal ulcers (DUs).

METHODS

Consecutive patients with symptoms of upper GI tract hemorrhage and a DU at the time of endoscopy were evaluated. The presence of H. pylori infection was determined by RUT, microbiology, and histology. Consecutive patients with uncomplicated DUs were similarly evaluated. The prevalence of H. pylori as determined by the RUT alone was compared to that determined by a combination of all tests in both patient groups.

RESULTS

Fifty-five patients with bleeding DUs and 69 with nonbleeding DUs were evaluated. The prevalence of H. pylori in patients presenting with bleeding was 72.7% (95% confidence interval [CI] 61.0-84.5%) and lower than the prevalence rate of 92.8% (95% CI 86.6-98.8%) in patients with uncomplicated PUD (p < 0.05). The prevalence of H. pylori in the bleeding DU group as determined by RUT alone (54.5%) was less than that determined by a combination of all tests (73%) with a false-negative rate of 10 of 40 (25%; 95% CI 11.6-38.4%) (p < 0.05). This false-negative rate was significantly greater than that observed in the group presenting with dyspepsia (1 of 64 [1.6%; 95% CI 0-4.6%]) (p < 0.01).

CONCLUSIONS

The prevalence of H. pylori is lower in patients with bleeding DUs when compared to patients with uncomplicated DUs. In addition, the sensitivity and negative predictive value of the RUT is lower in patients presenting with bleeding, and other methods of H. pylori diagnosis should be used in this patient group.

Admixture with whole blood does not explain false-negative urease tests

Rapid urease test sensitivity for Helicobacter pylori is reduced in the presence of active upper gastrointestinal bleeding. The aim of this study was to evaluate the in vitro effect of whole blood on rapid urease testing. Urease solution was added to normal saline, and heparinized whole blood both positive and negative for H. pylori antibody. The mixtures were then serially diluted in saline, and/or whole blood and added to three different rapid urease kits. The admixture of urease in H. pylori-seropositive whole blood diluted in either saline or whole blood enhanced performance in both kits fourfold compared with saline alone. No false-negative results were observed in either kit. Seronegative whole blood produced similar results. Undiluted saline or whole blood produced no positive rapid urease tests. Whole blood accelerates the urease reaction in vitro. Neither H. pylori antibody-positive nor -negative whole blood adversely impacted the rapid urease test. False-negative rapid urease test results in upper gastrointestinal bleeding cannot be explained by admixture with whole blood.

The effects of blood on rapid urease testing for Helicobacter pylori in mucosal biopsies from the gastric antrum

BACKGROUND

While the eradication of Helicobacter pylori in patients with bleeding peptic ulcer disease (PUD) decreases the rate of ulcer re-bleeding, the sensitivity of the rapid urease test (RUT) for H. pylori diagnosis is lower in this setting. The aim of this study was therefore to determine if exposing a gastric biopsy specimen to blood before its use in the RUT (CLOtest) could account for these findings.

METHODS

In patients undergoing endoscopy for the evaluation of dyspepsia gastric mucosal biopsies were obtained for H. pylori diagnosis (RUT, microbiology, and histology). Mucosal biopsies from each patient were also exposed to blood for 15, 30 and 45 minutes before use in the RUT.

RESULTS

Using a combination of diagnostic tests (histology, microbiology and routine CLOtest) as the 'gold standard', the sensitivity, specificity, positive predictive value and negative predictive value of the CLOtest remained above 90% despite prior exposure of the gastric biopsy specimen to blood, and these values were not significantly different from the performance characteristics of the CLOtest processed in a routine manner.

CONCLUSION

The exposure of gastric mucosal biopsy specimens to blood alone is not the explanation for the reduced sensitivity of the RUT in patients with bleeding peptic ulcers.