[706] Ancillary Stains Do Not Improve Helicobacter pylori Detection in Patients with Mild Disease, Even If Campylobacter-Like Organism (CLO) Tests Are Positive

Nicole C Panarelli, Dara S Ross, Oren E Bernheim, Zachary B Landzberg, Audrey N Schuetz, Stephen E Jenkins, Brian R Landzberg, Rhonda K Yantiss. Weill Cornell Medical College, New York, NY

Background: H. pylori detection in endoscopic biopsies is important because patients with chronic infection are at risk for gastric neoplasia. Ancillary stains may enhance H. pylori detection among patients with low bacterial load, but are increasingly ordered "up front" despite limited evidence supporting this practice. Most show sensitivities and specificities for H. pylori detection comparable to H&E stains when biopsies contain chronic gastritis and their utility in biopsies with absent, or scant, inflammation has not been fully evaluated. In this study, we assessed the value of immunohistochemistry, histochemical stains, and a flourochromatic dye for H. pylori detection in infected patients with biopsies that showed minimal, or no, chronic gastritis.
Design: We identified 56 patients with biochemical evidence of H. pylori infection [i.e. positive CLO tests] and gastric biopsies initially diagnosed as negative for organisms based on evaluation of H&E stained slides. All cases were subjected to H. pylori immunostains, Giemsa and Warthin-Starry histochemical stains, and a rapid flourochromatic dye (acridine orange). The H&E stained slides were re-evaluated for presence and severity of inflammation and H. pylori after interpretation of ancillary stains. Ten CLO test positive/biopsy positive and 10 CLO test negative/biopsy negative controls were stained in parallel.
Results: All 4 ancillary stains detected H. pylori in 100% of positive controls and were uniformly negative for H. pylori in negative controls. Ancillary stains were negative for H. pylori in 50 (89%) study cases that showed near-normal histology, but organisms were identified with all stains in the remaining 6 (11%), including the H&E stained sections that, in retrospect, showed chronic inactive gastritis in the antrum or fundus.
Conclusions: H&E stains adequately demonstrate H. pylori in most infected patients. Failure to detect bacteria usually reflects their absence in biopsy material, even in CLO test-positive patients, and ancillary tests do not substantially improve H. pylori detection, especially when biopsies contain uninflamed mucosae. However, scarce organisms may be overlooked, particularly when inflammation is mild. Thus, selective use of ancillary stains with a low threshold for ordering them is appropriate and cost-saving. Immunohistochemistry, Giemsa, Warthin-Starry, and acridine orange are similarly sensitive for bacteria detection. Acridine orange is a low-cost alternative that can be performed and interpreted in approximately 5 minutes, avoiding a delay in signout.
Category: Gastrointestinal

Wednesday, March 6, 2013 1:00 PM

Poster Session VI # 73, Wednesday Afternoon


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