There are 4 main blood groups: A, B, AB and O, of which group O is the most common. According to the American Red Cross, O- blood is the always the first to run out during a blood shortage due to its universality. Of the A blood types, A- is much rarer than A+, which is actually pretty common. How does blood typing work? Rh-null blood was first discovered in 1961 in an Australian Aboriginal woman. O+ blood is the most common blood type in the world and while it is not quite as universal as O- blood (O+ can be given to all Rh positive types but not the Rh negative types), it is still the most used blood, according to the American Red Cross. Approximately 10 to 20% of all people living in the world have this blood type, which is an interesting fact about B+ blood type. ... A positive is the second most common blood type. The Most Common Blood Type. The least common blood types are type B negative and type AB negative. The following map shows the distribution of the O, A, B, and AB blood types in the population by country in Europe (with colouring indicating the most common type, which in itself is not a reliable indicator of anything else; the actual figures are more important). In addition to the A and B antigens, there is a protein called the Rh factor, which can be either present (+) or absent (–), creating the 8 most common blood types (A+, A-, B+, B-, O+, O-, AB+, AB-). There are an additional 61 known antigens in the Rh system which can create millions of possible blood types. O+ blood is the most common blood type in the world and while it is not quite as universal as O- blood (O+ can be given to all Rh positive types but not the Rh negative types), it is still the most used blood, according to the American Red Cross. Similar to B- blood, A- blood can be donated to anyone with A or AB regardless of the positive or negative. On the other hand, those with A- blood can only get blood from A- and the universal donor O-. In general, the rarest blood type is AB-negative and the most common is O-positive. If both of your parents have blood type “A”, then your blood type will either be type “A” or “O”. AB-negative: 1 percentDifferent racial and ethnic groups typically see a different distribution. The rarest of these is type AB–. B negative. Of the eight basic blood types, AB- is the rarest with less than 1% (about 0.36%) of the world’s population sharing this type. As the “universal donor,” O- blood is perhaps the most valuable blood in the world as it can be given to nearly any blood type (except when the person has some rare antigen outside of the main ones). There are four major blood groups determined by the presence or absence of two antigens – A and B – on the surface of red blood cells. The most common blood types are A+, A–, B+, B–, O+, O–, AB+, and AB–. Just 2% of donors are B negative, making one of the rarest blood types. While people with A- blood can’t donate blood and plasma to just anyone, A- blood is valuable because it is the universal platelet donor and A- platelets can be given to anyone of any blood type. Globally, the most common blood type is O, but the most common blood type of Europeans is A. Since AB blood, both Rh positive and negative, contains no A or B antibodies it is the universal plasma donor and anyone from any blood group can receive plasma from AB blood. More about B negative. In the United States, the average distribution of blood types is as follows: 1. While O+ blood can be given to anyone with Rh positive blood types, individuals can only receive blood from O+ and O- donors. While AB- can receive blood from all other Rh negative types, it can only donate to others with AB blood, both Rh negative and positive. Additionally, Rh positive blood types are much more common than Rh negative blood types, which is another reason why O+ blood is always needed and important.