Accordingly, the color change occurs directly during the enzymatic reaction. This avoids the influence of the pH value of the sample (gastric biopsy) on the result of a selective urease test, which virtually eliminates the occurrence of false-positive results. If the pH value of the sample is shifted to the acidic side, for example, in the case of increased acidity of gastric juice, this also does not distort the result of the selective urease test . There is evidence to suggest that "H. pylori" moves proximal in the stomach in patients on therapy with proton pump inhibitors, and, as such, samples from the fundus and body should be taken in these patients. Active gastrointestinal bleeding reduces accuracy of the test. The specificity and sensitivity of this test is high compared with histopathological examination or urea breath test. The test is often done as part of point-of-care diagnostics, to eliminate the time and expense required to detect "H. pylori" on pathology testing.