The easiest way to test the blood type is to take human peripheral blood and put a drop on two slides. Then the blood is dripped with anti-A antibody serum and anti-B antibody serum respectively, and the blood is observed for agglutination reaction, and if there is agglutination reaction, the blood type can be determined. For example, if a person’s blood reacts with the anti-A antibody serum, it means that it is type A blood, and if it reacts only with the anti-B antibody serum, it means that it is type B blood. If a person’s blood reacts with anti-A antibody serum and anti-B antibody serum at the same time, the person’s blood type is AB. However, if the serum with anti-A antibody and anti-B antibody do not react, the person’s blood type is O. This is the easiest way to detect blood type.