Endoscopic biopsy requirements for post-treatment diagnosis of Helicobacter pylori.

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.