Tf mainly exists in plasma, the average content is about 1.20~3.25g/L. In healthy people faeces, there is almost no presence. When digestive tract bleeding, the Tf in serum flow into the gastrointestinal tract and excreted with faeces, it is abundant in faeces of gastrointestinal bleeding patients. Therefore, fecal Tf play a necessary and important role for the detection of gastrointestinal bleeding. The kit is a simple, visual qualitative test that detects Tf in human faeces, it has high detection sensitivity and strong specificity. The test based on high specificit double antibodies sandwich reaction principle and gold immunochromatographic assay analysis technics, it can give a result within 15 minutes.