Which is the Rarest Blood Type?

Here we will discuss the rarest blood type.

What factors influence blood type?

Genetics determines blood types. You get a pair of genes from your parents (one from the mother and one from the father) that determines your blood group.

What are the different blood types?

1. The ABO system

Each parent donates one ABO gene to their child. The genes A and B are dominant, while the O gene is recessive. Thus, if you have an O from your mother and an A from your father, your blood type is A. You also have a blood type of A if you inherit A antigens from both parents, giving you a blood type of AA or A. The inheritance of blood Type of B works similarly. On the other hand, you may inherit an A gene from one parent and a B gene from the other, resulting in the AB blood type. 

Overall, the six combinations of these genes are known as genotypes (AA, AB, BB, AO, BO, OO), which give rise to the four blood types, namely, A, B, AB, and O.

2. The Rh factor

The Rh factor is also used to classify blood. This is another antigen that may be discovered on red blood cells. If the cells contain the antigen, they are said to be Rh-positive. They are Rh-negative if they do not have it. Each blood type is assigned a positive or negative symbol based on whether the Rh antigen is present. Thus, taking into account the Rh factor, there are eight different blood types. 

Which blood group is the rarest?

AB negative

AB negative is the most uncommon of the eight major blood types, accounting for only 3% of our donors. The more detailed split-up of the number of people with the blood group is as follows:

• Caucasian: 1%
• African-American: 0.3%
• Latino-American: 0.2%
• Asian: 0.1%

AB- donors are universal plasma and platelet donors, which means that their plasma and platelets may be given to any patient.  Furthermore, people who are AB negative can receive blood donations from AB negative donors. Donors who are O negative as well as individuals with type A- negative blood. 

Other rare blood types are as follows:

Rhnull blood type

Rhnull blood is the most uncommon blood type. This substance is distinguished by a total absence of antigens in the Rh system. This includes the D antigen as well as 60 other antigens. This blood type is so uncommon that only 43 persons have ever been identified as having it, and there are only nine current donors. Furthermore, anybody with a rare blood type within the Rh system can accept it. Hence it is referred to as “golden blood”, as it is worth more than its weight in gold.

Ro blood type

The Ro blood type is a subtype of the Rh-positive blood type. You can have this subtype regardless of whether you have O, A, B or AB blood type. The Ro subtype is very essential for two reasons

• Demand is growing by 10-15% each year, and just 2% of frequent donors have the Ro subtype.
• Ro blood is essential in the treatment of sickle cell disease, which is a set of genetic blood abnormalities affecting red blood cells. 

What causes blood types to be so rare?

Although the ABO and Rh blood types are the most crucial for blood transfusions, there are 36 more blood groups that are recognised.

Each blood type has a unique set of carbohydrates and proteins known as antigens, which are present on the exterior of red blood cells. There are over 600 antigens, therefore there is a lot of room for diversity between persons. You may have a rare subtype if your blood contains uncommon antigens or lacks common antigens.  

Why do we need to donate rarest blood types?

People who have a specific antigen do not create antibodies against it, but they do produce antibodies against the other antigens in the group. For instance, if a person has type A blood, he or she will produce antibodies against the B antigen but not the A antigen.

That is, if this individual is given either type B or type AB red blood cells, his or her antibodies will attack and kill the foreign red blood cells with the B antigen, resulting in an adverse response. Similarly, a person who has the RhD antigen will not produce antibodies against the RhD antigen, but an RhD negative person will produce antibodies against blood containing RhD positive red cells. Thus, it is important to give the right blood type. The table below mentions the mating blood types for each blood group.  

The ABO and Rh groups are used in the majority of blood transfusions.

However, if a person requires regular transfusions, blood that closely matches their own works best. If you have a rare subtype, your blood might be critical for another patient who has the same subtype.