Blood Groups area classification is based on the presence and absence of antibodies and inherited antigenic substances on the surface of red blood cells. These antigens may be proteins, carbohydrates, glycoproteins, or glycolipids, depending on the blood group system. Several of these red blood cell surface antigens can stem from one allele, or an alternative version of a gene and collectively form a blood group system.
Blood Group System
Karl Landsteiner is an Austrian scientist who discovered the ABO blood group system in the year 1900. In his experiments, He mixed different blood types and noted that the plasma from certain blood types produced agglutinates or formed clusters which were caused by the absence of molecules on red blood cells and resulting in antibodies to defeat that molecule. He then made a note of the agglutination and divided the blood types into 4 different groups. For the discovery of the ABO blood group, He was awarded the Nobel Prize in 1930 in Physiology.
Blood types are inherited and represent contributions from both parents. As of 2019, a total of 38 human blood group systems are recognized by the International Society of Blood Transfusion (ISBT). They are 2 most important blood group systems are ABO and Rh; they determine someone’s blood type (A, B, AB, and O, with +, − or null denoting RhD status) for suitability in blood transfusion.
Different Blood Groups
There are 8 different blood types:
- A positive: It is one of the most common blood types (35.7% of the U.S. population has it). Someone with this type can give blood only to people who are A positive or AB positive.
- A negative: Someone with this rare type (6.3% of the U.S. population) can give blood to anyone with A or AB blood type.
- B positive: Someone with this rare type (8.5%) can give blood only to people who are B positive or AB positive.
- B negative: Someone with this very rare type (1.5%) can give blood to anyone with B or AB blood type.
- AB positive: People with this rare blood type (3.4%) can receive blood or plasma of any type. They’re known as universal recipients.
- AB negative: This is the rarest blood type — only 0.6% of the U.S. population has it. Someone with this blood type is known as a “universal plasma donor,” because anyone can receive this type of plasma.
- O positive: This is one of the most common blood types (37.4%). Someone with this can give blood to anyone with a positive blood type.
- O negative: Someone with this rare blood type (6.6%) can give blood to anyone with any blood type.
Universal Donor and Universal Recipient
O negative blood contains no A, B, or RhD antigens. Almost anyone with any blood type can receive these red blood cells. A person with group O negative blood is a universal donor.
- A person with O-negative blood can donate to almost anyone.
- A person with Rh-negative blood can donate to a person with Rh-negative or Rh-positive blood.
- A person with Rh-positive blood can only donate to someone with Rh-positive blood.
- A universal plasma donor will have type AB blood.