what does a blood test checking colon mean
Polyps or tumours in the colon have blood vessels that can release a small amount of blood onto the stool when it passes by. Stool tests check for this occult (hidden) blood that you canât see with your eyes. Two types of stool tests are used in Canada to screen for colorectal cancer.Guaiac-based fecal occult blood test (gFOBT). Uses a chemical reaction on a paper card to find traces of blood in the stool.ther reasons for having blood in the stool. Having blood in your stool doesnât always mean that you have polyps or cancer. Blood may come from the colon or from other parts of the digestive tract, such as the stomach or anus. The bleeding can be caused by: 1  ulcers (sores on the lining of your digestive tract).