Retrospective analysis of discordant results between histology and other clinical diagnostic tests on helicobacter pylori infection

ARTICLE HIGHLIGHTS

Research background

Determining Helicobacter pylori (H. pylori) status is essential in the management of H. pylori-related diseases. No single test is universally recognized as the gold standard alone. Typically, symptomatic patients at our hospital undergo upper GI endoscopy with biopsy, often accompanied by an additional H. pylori test. The results generally align with each other, although discrepancies arise occasionally.

Research motivation

The clinician places particular emphasis on gastric biopsy results, especially when supplemented with immunohistochemistry (IHC), often considering it the most accurate. Rare cases where biopsy results are negative while other clinical tests show positivity can present challenges for clinicians.

Research objectives

The goal of this retrospective study is to examine the discordance between histopathology and alternative H. pylori tests, explore the underlying causes, and assess the implications for clinical management.

Research methods

Pathology reports of gastric biopsies were retrospectively retrieved from August 2013 to July 2018. Inclusion in the study required the presence of other H. pylori tests within seven days of the biopsy, including rapid urease test (CLO test), stool antigen test (SA), and H. pylori culture. The concordance between histopathology and other tests was evaluated based on result consistency. In cases where histology was negative while other tests showed positivity, the slides underwent reassessment, and the clinical chart was examined.

Research results

1396 pathology reports were identified, each accompanied by one additional H. pylori test. The concordance rates between biopsy and other tests did not show significant differences based on the number of biopsy fragments. 117 discrepant cases were identified. Only 20 cases (9 with CLO test and 11 with SA) had negative biopsy but positive results in other tests. Four cases initially stained with Warthin-Starry stain turned out to be positive for H. pylori with subsequent IHC staining. Among the remaining 16 true discrepant cases, 10 patients were on proton pump inhibitors before the biopsy and/or other tests. Most patients underwent treatment, except for two who were untreated, and two patients who were lost to follow-up.

Research conclusions

Our findings reveal that both SA and CLO test demonstrate high concordance rates with histological diagnoses. The concordance rate between histology and H. pylori culture is slightly lower, mainly due to the lower sensitivity of the H. pylori culture assay. Importantly, the concordance rate remains consistent regardless of the number of gastric biopsy fragments. Rare instances of discrepancies exist, where H. pylori diagnosis is negative by histology but positive by SA or CLO test. Multiple factors may contribute to the discordance. Despite histological examination showing negative results for H. pylori in these cases with discrepancies, most patients still received treatment. Correlation with clinical history, past laboratory results, and follow-up testing may aid in clinical management.

Research perspectives

This retrospective study was conducted at a singular tertiary medical center. It would be intriguing to conduct similar retrospective research in other hospitals to compare discordance rates between histology and other H. pylori tests and variations in clinical management.