The reasons for failure to donate blood are: First, people with abnormal liver function cannot donate blood. Before donating blood, liver function is usually tested, and if liver function is abnormal, such as a significant increase in transaminases, you cannot donate blood. Second, if the patient is positive for hepatitis B antibody, hepatitis C antibody, syphilis antibody, HIV antibody, these have blood-borne infectious diseases, you can not donate blood, because the blood donated by these patients is contagious, can be transmitted to normal people, so that others infected with the disease, so you can not donate blood. Third, if the donor’s weight is not up to the standard, he or she cannot donate blood. China stipulates that a donor cannot donate blood if his or her weight does not reach 50 kg or more. Anemic patients cannot donate blood. If anemic people donate blood, it will aggravate their own anemia and cause serious effects on their bodies, so they cannot donate blood.