O- blood used to be considered the universal blood donor but now medicine knows that there are other factors in the blood that can cause rejection from the body.
http://www.mayoclinic.org/tests-procedures/blood-transfusion/expert-answers/universal-blood-donor-type/faq-20058229
Your body may not be used to different types of blood and may try to defend itself
Type O positive is the universal donor and can donate to any type.
They can only donate to other AB types, but they can receive blood from A, B, or O.
Yes. O- can donate to all blood types. O+ can only donate to other positive blood types, including AB+.
The only type O can receive from is O. O - can only receive from O -, but can donate to A, B, AB or O, either + or -. O + can receive either but can only donate to A, B, AB or O Rh +.
Type A blood can only be donated to others with Type A blood or AB blood.
More than just two blood types are not compatible with each other. The four basic types of blood are: A, B, AB, O(not counting Rh). Type A blood can only receive blood from type A and type O. However, type A blood can donate their blood to type A and type AB. Type B blood can only receive blood from type B and type O. However, type B blood can donate their blood to type B and type AB. Type AB blood can receive blood from every type, A, B, AB, and O. However, type AB blood can only donate to other AB. Type O blood can only receive blood from type O. However, type O can donate their blood to A, B, AB, and O. So, AB is the "universal" reciepient and O is the "universal" donor.
People who have AB blood are the universal recipient. They can receive blood from any blood type which can come in handy in an emergency situation requiring blood.
The four different types of blood are: A, B, AB, and O. When you donate blood, or have blood drawn, at the hospital, they will tell you which type you have,and usually give you a card to identify your blood type on your identification.
Anyone can donate blood.The tricky part is deciding which person can receive your blood - it's based on blood types. Type O, for example, can only receive more type O and you also have to match up the Rh factor for + or - (+ can receive anything, - can only take more - blood). Type AB can receive any blood so long as the Rh factor matches up properly.
It's important for anyone who can donate blood to donate, but the fact is that AB is not a donor for any blood type but its own. AB can only donate to AB. AB is, however, what is referred to as a universal recipient, meaning that someone with type AB blood can receive blood from AB, A, B, and O blood types. This being the case, it wouldn't seem that a shortage of AB blood would be a problem unless there is a generalized blood shortage of all types (which there usually is, so donate if you can spare a pint!)
Blood AB.
Not taking Rh Factor into consideration, O is the universal donor. All blood types can receive type O. For information, AB is the universal recipient. They can take any blood type. Remember, this excludes the Rh Factor.
The different blood types are listed by their letters, and are represented by what blood types they can donate to/receive from. The chart on red cross' website goes from top to bottom according to type.