Comparison of invasive methods and two different stool antigen tests for diagnosis of H pylori infection in patients with gastric bleeding

Abstract

Aim: To compare two different H pylori stool antigen tests as noninvasive diagnostic methods.

Methods: The study population consisted of 22 upper gastrointestinal system bleeding patients. Urea breath test (UBT), rapid urease test (RUT) and histopathological examination were applied to all patients. Stool specimens from these patients were examined by rapid STRIP!HpSA and one step simple H pylori antigen cassette test for the detection of H pylori antigens.

Results: For these 22 patients, 15 (68.2%) were diagnosed as positive and seven (31.8%) were diagnosed negative for H pylori infection by the gold standard methods. Whereas 10 (45.5%) were positive and 12 (54.5%) were diagnosed negative by the rapid STRIP!HpSA test. The sensitivity, specificity, positive and negative predictive values were 60%, 86%, 90% and 50%, respectively. When compared to the gold standard methods, these differences were not significant. However, six patients (27.3%) were positive, and 16 (72.7%) were negative by the simple H pylori stool antigen cassette test. The sensitivity, specificity, positive and negative predictive values were 33%, 86%, 83% and 38%, respectively. Compared to the gold standard methods, the simple H pylori stool antigen cassette test results were significantly different (P = 0.012).

Conclusion: Rapid STRIP!HpSA test could be used as a routine diagnostic tool in the microbiology laboratory for assessing clinical significance and eradication control of H pylori in upper gastrointestinal system bleeding patients.