There are four main types of diseases that are transmitted through blood, namely hepatitis B, hepatitis C, AIDS and syphilis. Therefore, it is necessary to check these items before donating blood and before blood transfusion, or before performing surgical operations. Because whenever the operation of seeing blood occurs, there is a possibility of disease transmission through the operation, so it should be clarified in advance. In addition to these diseases, other diseases that can produce viraemia or produce bacteraemia may also be transmitted through the blood route. But many other diseases have easier ways of transmission, such as influenza, which can be transmitted entirely through respiratory droplets. Also the time period leading to viremia is relatively short and the probability of transmission to other people through the blood is very small, so it is not too much of a clinical concern.