Evaluation of the effect of presence of blood in the stomach on endoscopic diagnostic tests for Helicobacter pylori infection

Upper gastrointestinal bleeding: Diagnosis of Helicobacter pylori infection-Descriptive study

Background and Aim

The presence of blood in the stomach has been thought to affect the performance of diagnostic tests used in detecting Helicobacter pylori (H. pylori) in the stomach. This study evaluates the effect of upper gastrointestinal bleeding on the efficacy of a rapid urease test (RUT) and compares the results with the pathologic method.

Methods

In this descriptive study, 100 patients presented with upper gastrointestinal bleeding, confirmed from endoscopy, referred to Shahid Rahimi Hospital in Khorramabad were enrolled. Antral biopsy was performed in all the patients and the samples were extracted for histopathology and RUT. A questionnaire was used to collect rapid urease test outcomes and associated parameters (antibiotic, bismuth, and proton pump inhibitors), histology and demographic data. Histopathology was used as the gold standard for diagnosis of H. pylori.

Results

Of the 52 patients who were reported positive for H. pylori in pathology, 36 had RUT-positive H. pylori, sensitivity 69.2%, and of 48 patients whose pathology was negative, 25 had negative RUT, specificity 52.1%. Of 59 RUT, 36 had positive pathology, positive predictive value was 61% and from 41 with negative RUT, 25 had negative pathology, negative predictive value was 61%. The prevalence of H. pylori infection was significantly associated with the age of 50 years and above, p = 0.042, and previous history of bleeding, p = 0.019.

Conclusion

Gastrointestinal bleeding can reduce the sensitivity of RUT. The negative results of these tests in acute upper gastrointestinal bleeding should therefore be interpreted carefully.

Increasing biopsy number and sampling from gastric body improve the sensitivity of rapid urease test in patients with peptic ulcer bleeding

BACKGROUND

Previous studies demonstrated that the sensitivity of rapid urease test (RUT) for diagnosis of Helicobacter pylori infection decreased during peptic ulcer bleeding.

AIM

We designed this study and tried to find a better method to improve the detection rate of H. pylori infection at the same session of endoscopic diagnosis of peptic ulcer bleeding.

METHODS

We prospectively enrolled 116 patients with peptic ulcer bleeding. These patients received intravenous proton pump inhibitor and then received upper gastrointestinal endoscopy within 24 h after arrival. We took one piece of biopsy from gastric antrum (Group 1), four pieces from gastric antrum (Group 2), and one piece from the gastric body (Group 3) for three separate RUTs, respectively. (13)C-urease breath test was used as gold standard for diagnosis of H. pylori infection.

RESULTS

There were 74 patients (64 %) with positive (13)C-urease breath test. Among these 74 patients, 45 patients had positive RUT (sensitivity: 61 %) in Group 1; 55 patients had positive RUT (sensitivity: 74 %) in Group 2; 54 patients had positive RUT (sensitivity: 73 %) in Group 3. There were significant differences between Group 1 and Group 2 (p = 0.02) and between Group 1 and Group 3 (p = 0.022).

CONCLUSIONS

The sensitivity of RUT was 61 % during peptic ulcer bleeding. The sensitivity of RUT can be increased significantly by increased biopsy number from gastric antrum or biopsy from gastric body.