guaiac test การใช้

• There is no consensus on whether to stop warfarin before a guaiac test.
• Stool guaiac test for fecal occult blood ( gFOBT ) sensitivity varies depending on the site of bleeding.
• Further discussion of sensitivity and specificity issues that relate particularly to the guaiac method is found in the stool guaiac test article.
• Proposed oxidations of compounds in guaiac oil as explanation for the formation of the blue bis-methylenequinone as part of the guaiac test.
• The stool guaiac test was originally the principal colon cancer screening technology available, but modern tests which look for globin or DNA are now also available.
• The stool guaiac test method may be preferable to fecal immunochemical testing ( FIT ) if there is a clinical concern about possible gastric or proximal upper intestinal bleeding.
• Even when using anticoagulants a high proportion of positive guaiac tests were found to be due to diagnosable lesions, suggesting anticoagulants may not cause bleeding unless there is an abnormality.
• However, although heme breakdown is less than globin during intestinal transit, false negative results can be seen with the stool guaiac tests due to degradation of the peroxidase-activity.
• The stool guaiac test for hidden ( occult ) blood in the stool can be done at home or in the doctor's office, or can be performed on samples submitted to a clinical laboratory.
• The sensitivity of a single stool guaiac test to pick up bleeding has been quoted at 10 to 30 %, but if a standard three tests are done as recommended the sensitivity rises to 92 %.
• Conversely, 800 mg of cimetidine 1 hr before the start and again at 50 miles of a 100-mile running race substantially decreased GI symptoms and postrace guaiac test positivity but did not affect race performance.