Should we rely on rapid urease test or routine staining for the accurate diagnosis of helicobacter pylori

Abstract

SHOULD WE RELY ON RAPID UREASE TEST OR ROUTINE STAINING FOR THE ACCURATE DIAGNOSIS OF HELICOBACTER PYLORI RK Hsu MD M Chang MD, A Yu MD, B Yost* MD, B Ruebner* MD, JG Lee MD and JW Leung MD. Division of Gastroenterolgy and Department of Pathology*, University of California, Davis Medical Center, Sacramento CA Introduction Rapid Urease Test and histology are two common endoscopic tests for Hp detection. Discrepancies between these two tests can cause confusion in the actual diagnosis. In praetice, Genta stain is more sensitive than H&E and Giemsa stain but are not used in routine. The aim of this study is to examine the error rate of RUT and histology using routine staining as reference to the consensus results by pathologists with special interest in GI pathology. Method: Standard antral biopsy were obtained from 40 outpatients presented with ulcer and nonulcer dyspepsia using Wilson Cook Maxum biopsy forceps with cup diameter 2.5mm. The patients were not on treatment with proton pump inhibitors. The HP status was detected using Hpfast rapid urease test (RUT) and initial histology by routine H&E or Giemsa stain interpreted by general pathologists. The histology slides were then reviewed by two pathologists with special interest in GI pathology who were blinded to the initial results. Genta stain was used for the final diagnosis in doubtful cases. Using these consensus results as the gold standard, comparison of the error rate of RUT and general staining was made. The Hpfast RUT results were reevaluated independently by l0 different physicians and nurses. Results: (n = 40) Error rate with 95% Confident interval Group # error Rate SE U95 L95 RUT 16 0.4 0.l 0.9544 0.2614 H&E/Giemsa 4 0.1 0.05 0.2386 0.0307 The greatest discrepancies in the interpretation of Hpfast results were observed at the color change that were seen at the range of pH 5.8-6.5. Conclusions: 1. Inter-observational variability in the interpretation of color changes in Hpfast RUT in the marginal cases could be a factor for the discrepancies seen in routine practice. A single trained observer may avoid the problem. 2. When both tests agree with each other, the accuracy rate is 92%. 3. In doubtful cases with routine staining, Genta stain is required to confirm the diagnosis.