What is the name of the test used to identify blood in the stool?

The guaiac test is a specific method used to detect the presence of hidden (occult) blood in stool samples, which can indicate a variety of conditions, including colorectal cancer or gastrointestinal bleeding. This test employs guaiac resin, which reacts to heme, the iron-containing component of hemoglobin. When blood is present in the stool, the guaiac paper changes color, signaling a positive result.

While both the hemoccult test and the fecal occult blood test essentially refer to the same concept, using guaiac as a reagent specifically identifies the test's traditional name. Colonoscopy, on the other hand, is a diagnostic procedure that allows direct visualization of the colon and rectum but is not a direct test for blood in stool. Thus, the specific identification of the test as the guaiac test reinforces its role in initial screenings for gastrointestinal bleeding and its historical significance in the detection of colorectal cancer.