The Influence of Biopsy Number and Site on the Sensitivity of Rapid Urease Test for Diagnosis of H. Pylori Infection in Patients With Bleeding Gastroduodenal Ulcer

Rapid urease test (RUT) is the most commonly used biopsy-based method to diagnose Helicobacter pylori (Hp) infection because of its simple, rapid and accurate characters. However, its sensitivity was reported to decrease during ulcer bleeding recently. So it is an important issue to avoid a false negative test in these patients. Siddique et al reported that the sensitivity of RUT could be increased when the biopsy number increased from 1 to 4. Other studies demonstrated that additional biopsy from gastric body would increased the sensitivity of RUT in patients with ulcer bleeding. Therefore, we design this study to see if increased number of biopsy or different location of biopsy could increase sensitivity of RUT in patients with gastroduodenal ulcer bleeding.

After receiving explanation and giving consent, these patients with gastric or duodenal ulcer bleeding diagnosed after endoscopic examination will be enrolled. Those who are unstable, have received antibiotic or continuous proton pump inhibitor treatment within 4 weeks, or are contraindicated for endoscopic biopsy will be excluded. We will take 1 piece, 4 pieces of biopsy samples from prepyloric antrum and 1 piece from gastric body with standard biopsy forceps from the patients after they agree for RUT test. Then, we put these samples into 3 separate RUT kits respectively. We use 13C-UBT as gold standard for diagnosis of Hp infection. It is scheduled: (1) if the condition of this patient is not suitable for breath test just after endoscopic examination, 13C-UBT will be performed within 2 days,(2) otherwise, it will be performed 1 hour after examination. We plan to enroll 100 patients for this study. We will apply McNamer's test to examine the difference of RUT sensitivity of different biopsy number. For the RUT sensitivity from different locations, we use kappa statistic method to analyze their consistency.