Medical professionals need to know what the blood type is of an injured person to keep them alive and well. Knowing blood types is important because not all blood types can receive other blood types. Blood Type AB is the universal recipient, and can receive blood from any of the 4 blood types. Type AB is the universal recipient because they lack both A and B proteins making it possible to receive both type A or B blood. Red Blood Cells are the main reason why it is not possible for certain blood types to receive certain types of blood. For example, type A cannot receive type B blood or vice versa. Blood analysis can also help crime scene investigators narrow down suspects. Using a blood stains left at the scene of a crime, and after differentiating the blood of the victim from the blood of the criminal, investigators can find the blood type of the criminal blood and use that blood to eliminate possible suspects. For example if Blood type B blood was left at the scene of the crime and identified to be the criminals blood and not the victim, police can use that evidence to eliminate possible suspects from their list that have a different blood type. I am curious to find out what blood type I am.Â