A positive immunoassay for fecal occult blood means that there is a small amount of bleeding in the digestive tract. Fecal occult blood, also known as fecal occult blood test, refers to the fact that although the red cells in the digestive tract are digested and decomposed when the bleeding is relatively small, the red color is not visible on the surface of the stool, and no red cells are found under the microscope, but the bleeding in the digestive tract is present, so it belongs to a positive occult blood test. Under normal circumstances, the fecal occult blood test of the digestive tract should be negative. The fecal occult blood test is one of the most commonly used screening tests for fecal examination and can be used as a screening indicator for the screening of malignant tumors in the digestive tract. If it is a continuous test, it is of great value for early detection of colon cancer, stomach cancer and other malignant tumors. In particular, asymptomatic middle-aged and elderly people over 50 years old should do stool occult blood test once a year, so it is an important indicator for the screening of GI malignancies and has a high specificity. Although it cannot reach 100%, it has important diagnostic and differential value in combination with clinical. It can also be used as a differentiator between ulcers and tumors and peptic ulcers, and the general positive rate can reach 40%-70%. Intestinal bleeding is usually intermittent, and gastrointestinal malignancies can be as high as 95% and can be persistently positive. It can also be used as an important evaluation indicator for the diagnosis of GI bleeding. Any disease or injury that causes GI bleeding can result in a positive fecal occult blood test solution.