Accuracy of CLOtest after Helicobacter pylori therapy

doi:10.1016/S0016-5107(98)70321-9

Gastrointestinal Endoscopy

Volume 47, Issue 3, March 1998, Pages 250-253

https://doi.org/10.1016/S0016-5107(98)70321-9 Get rights and content

Abstract

Background: The accuracy of rapid urease testing after Helicobacter pylori therapy has not been widely studied and might be diminished because of decreased numbers of organisms. We assessed CLOtest results after therapy in two randomized, double-blind trials. Methods: A total of 233 patients (in two separate studies) with true-positive baseline CLOtests (by histology or culture) received 2 weeks of omeprazole/amoxicillin, omeprazole, or amoxicillin. In study 1, patients received an additional 2 weeks of omeprazole therapy (20 mg/day) or placebo; no additional therapy was given in study 2. Endoscopy was repeated 4 weeks after completion of therapy in both studies. A diagnosis of cure required at least two negative endoscopic biopsy tests (histology, culture, CLOtest) and no positive tests. Results: After therapy, 178 patients (76%) remained positive for H. pylori by histology and/or culture for both studies combined. Post-therapy CLOtest sensitivity was 86% and specificity was 95%. Sensitivity was poorer in patients after dual therapy than after monotherapy in both study 1 (68% vs. 89%; p = 0.03) and study 2 (75% vs. 94%; p = 0.03). Conclusions:CLOtest sensitivity after therapy was lower than expected in our large group of patients with baseline true-positive CLOtests. In addition, sensitivity was lower after the use of more effective therapy (i.e., dual therapy as compared with monotherapy). Although most patients with unsuccessful treatment will be identified with the CLOtest alone, a negative result should not be taken as diagnostic of eradication. (Gastrointest Endosc 1998;47:250-3.)

Section snippets

Methods

Two well-controlled randomized, double-blind studies were conducted to assess the efficacy of treatment with an omeprazole plus amoxicillin regimen in eradicating H. pylori in patients with duodenal ulcer disease and H. pylori infection. A secondary objective of these studies was to compare the H. pylori eradication rates based on a CLOtest with the results based on culture and histologic examination. Patients from two separate treatment trials with a true-positive CLOtest of an antral biopsy

Results

A total of 233 patients with true-positive baseline CLOtests (i.e., confirmed by positive histologic examination and/or positive culture) in the two studies were included. After therapy 178 patients (76%) remained positive for H. pylori by histology and/or culture: 48 (49%) of 98 patients receiving omeprazole/amoxicillin dual therapy and 130 (96%) of 135 patients receiving monotherapy with either omeprazole or amoxicillin for the 2 studies combined.

The results after therapy for studies 1 and 2

Discussion

Recommendations for diagnostic testing for H. pylori infection must be differentiated according to whether the patient is undergoing initial screening for the infection or is being evaluated after therapy. Even with unsuccessful therapy, the number of organisms decreases—generally below the ability of any diagnostic test to detect the infection. The number of organisms then increases, and, by 4 weeks or more after therapy, the number of organisms is generally sufficient for diagnosis by

References (4)

L Laine et al.
Prospective comparison of commerically available rapid urease tests for the diagnosis of Helicobacter pylori
Gastrointest Endosc
(1996)
L Laine et al.
The influence of size or number of biopsies on rapid urease test results: a prospective evaluation
Gastrointest Endosc
(1996)

There are more references available in the full text version of this article.

Cited by (20)

Tissue sampling and analysis
2003, Gastrointestinal Endoscopy
Endoscopic biopsy requirements for post-treatment diagnosis of Helicobacter pylori
2000, Gastrointestinal Endoscopy
Background: Data on sensitivities of biopsy tests for Helicobacter pylori diagnosis after modern eradication therapy are limited. We assessed diagnostic yield of endoscopic biopsy tests before and after therapy in 2 U.S. multicenter double-blind trials of 10-day proton pump inhibitor–based triple therapy versus dual antibiotic therapy. Methods: Three hundred one patients with duodenal ulcer and H pylori infection had endoscopy at baseline and at 8 weeks. Four antral and 3 body biopsies were taken at both endoscopies: 1 antral biopsy for a rapid urease test (CLOtest), 2 antral and 2 body biopsies for histologic examination (Genta stain), and 1 antral and 1 body biopsy for culture. Results: The 2 same-site biopsies (antral or body) for histologic examination were in agreement in 97% of cases before treatment and 100% after triple therapy. Histologic examination of antral biopsies without body biopsies missed H pylori infection in 2% of patients before treatment and 5% after triple therapy. Posttreatment sensitivities for triple therapy were significantly lower than pretreatment sensitivities for all tests (e.g., 18% decrease in sensitivity in antral histology, 22% decrease in antral culture); decreases in sensitivity were greater after triple therapy than after the less effective dual therapy. CLOtest plus histology had a post-treatment sensitivity of 96% in the triple therapy group. Conclusions: A single antral biopsy for histology provides excellent sensitivity for H pylori in untreated patients, but, after effective therapy, sensitivities of biopsy tests decrease. Use of more than one method of testing may increase diagnostic yield when assessing post-treatment H pylori status with endoscopy, whereas the addition of multiple biopsies for each type of test is of more limited value. (Gastrointest Endosc 2000;51:664-9.)
Evaluation of rapid antibody tests for the diagnosis of Helicobacter pylori infection
2000, American Journal of Gastroenterology
Citation Excerpt :
They are relatively easy to perform although their designs and complexity vary with the Accustat being the most complex to use and the StatSimple pylori the least. Unlike tests that rely on bacterial urease activity (UBT and RUT), which may yield false-negative results in patients taking proton pump inhibitors, bismuth compounds, or antibiotics (6, 23, 24), antibody tests are not effected by these medications. The whole blood tests are among the least expensive tests available, costing less than $15 per test.
OBJECTIVE:
The aim of this study was to compare the performance characteristics of one serum and four whole blood rapid antibody tests for Helicobacter pylori infection.
METHODS:
A total of 97 outpatients referred for endoscopic evaluation of dyspepsia were included. Antral biopsies were obtained for histology and rapid urease test. Serum was tested with an enzyme-linked immunoassay (HM-CAP) and a rapid serology test (FlexSure HP). A commercially available ¹³C-urea breath test was performed. Capillary blood obtained by fingerstick was tested with FlexSure HP, QuickVue, Accustat, and StatSimple pylori tests. Sensitivity, specificity, and accuracy of each rapid test was calculated relative to a criterion standard of histological gastritis and at least two of the four following tests positive: identifiable organisms on specially stained slides, rapid urease test, urea breath test, or serum immunoassay.
RESULTS:
A total of 30 patients (31%) were infected. The FlexSure HP Serum, and FlexSure HP, QuickVue, Accustat, and StatSimple pylori whole blood tests had sensitivities of 90%, 87%, 83%, 76%, and 90%; specificities of 94%, 90%, 96%, 96%, and 98%, and accuracies of 93%, 88%, 92%, 87%, and 96%, respectively. Sensitivities were not statistically different. StatSimple pylori was more specific than FlexSure HP whole blood (p < 0.03), and more accurate than FlexSure whole blood (p < 0.024) and Accustat (p < 0.01). Serum immunoassay was significantly more sensitive (97%) than FlexSure whole blood, QuickVue, and Accustat (p < 0.01), but its specificity (95%) was not statistically different from the rapid tests.
CONCLUSION:
Rapid antibody testing provides an accurate diagnosis of H. pylori infection. In general, these tests are less sensitive than, but as specific as, standard serology.
A prospective evaluation of new rapid urease tests before and after eradication treatment of Helicobacter pylori, in comparison with histology, culture and <sup>13</sup>C-urea breath test
2000, Gastrointestinal Endoscopy
Background: The rapid urease test is a simple and cost-effective method to detect Helicobacter pylori in biopsy specimens. The aim of this study was to evaluate the accuracy of two new rapid urease tests, Helicocheck and PyloriTek, before and after eradication. Methods: A total of 278 patients, including 115 patients who had not undergone eradication of H pylori and 163 patients after eradication treatment, were enrolled. Eight biopsy specimens were taken from both the antrum and the body of the stomach for histology, culture, and two rapid urease tests. Assessment of H pylori infection was determined by the combination of histology, culture, and ¹³C-urea breath test. Results: Overall sensitivity, specificity, and positive and negative predictive values of the Helicocheck before eradication were 91.0%, 100%, 100%, and 62.5%; PyloriTek, 92.0%, 100%, 100%, and 65.2%. Those of Helicocheck after eradication were, respectively, 60.5%, 99.2%, 95.8%, and 89.2%; PyloriTek, 60.5%, 99.2%, 95.8%, and 89.2%. For the Helicocheck, determination of the infection status of H pylori by biopsies from the gastric body had a significantly higher sensitivity than antral biopsies. After eradication, the combination of 1 antral biopsy and 1 biopsy from the body was not effective enough to improve the overall sensitivity. Conclusions: Helicocheck and PyloriTek have equally satisfactory overall sensitivity before eradication treatment. However, the sensitivity of these rapid urease tests was lower after eradication than before eradication. (Gastrointest Endosc 2000;51:164-8.)
Evaluation of Accuracy and Feasibility of a New-Generation Ultra-Rapid Urease Test for Detection of Helicobacter pylori Infection
2022, Gastrointestinal Disorders
Evaluating the Accuracy of the Endoscopic ABC Classification System in Diagnosing Helicobacter pylori -Infected Gastritis
2020, Digestion

View all citing articles on Scopus

^☆: From the University of Southern California School of Medicine, Los Angeles; and Astra Merck, Wayne, Pennsylvania.

^☆☆: Supported in part by Astra Merck.

^★: Reprint requests: Loren Laine, MD, GI Division (LAC 12-137), Department of Medicine, USC School of Medicine, 2025 Zonal Ave., Los Angeles, CA 90033.

^★★: 31/1/87365

View full text

Article preview

Gastrointestinal Endoscopy

Abstract

Section snippets

Methods

Results

Discussion

References (4)

Prospective comparison of commerically available rapid urease tests for the diagnosis of Helicobacter pylori

Gastrointest Endosc

The influence of size or number of biopsies on rapid urease test results: a prospective evaluation

Gastrointest Endosc

Cited by (20)

Tissue sampling and analysis

Endoscopic biopsy requirements for post-treatment diagnosis of Helicobacter pylori

Evaluation of rapid antibody tests for the diagnosis of Helicobacter pylori infection

A prospective evaluation of new rapid urease tests before and after eradication treatment of Helicobacter pylori, in comparison with histology, culture and <sup>13</sup>C-urea breath test

Evaluation of Accuracy and Feasibility of a New-Generation Ultra-Rapid Urease Test for Detection of Helicobacter pylori Infection

Evaluating the Accuracy of the Endoscopic ABC Classification System in Diagnosing Helicobacter pylori -Infected Gastritis

Accuracy of CLOtest after Helicobacter pylori therapy☆,☆☆,★,★★

Abstract

Section snippets

Methods

Results

Discussion

Gastrointest Endosc

Gastrointest Endosc