Find out about the blood groups and their importance.

Question

Philoid · Accepted Answer

Carl Landsteiner (1900) discovered that there are two types of antigens present on the plasma membrane of the RBC. These are antigen A and antigen B. These are also called corpuscle factors. There are also two types of antibodies present in the plasma. These are antibody A (Anti-A) and antibody B (Anti-B). These are also called plasma factors. The blood is classified into four groups on the basis of the presence or absence of these antigens. These groups are A, B, AB and O. This system of classification of blood is called: ‘ABO’ system.

The following table shows the types of blood groups and their antigens and antibodies:

Blood group

Antigen on RBC

Antibody in Plasma

A

B

AB

O

A

B

A and B

O

Anti-B

Anti-A

None

Anti-A and Anti-B

Along with the A and B antigens or antibodies many people have another factor called the Rh factor. This is an antigen first found in Rhesus monkey (hence, called the Rh factor). People whose red blood cells contain the Rh antigen are said to be Rh positive (Rh⁺). People who lack it are called Rh negative (Rh^-). A person with Rh blood does not have Rh antibody (which destroys Rh antigen) naturally. But, as and when an Rh antigen enters the blood, it develops and destroys the antigen.

If a person with blood group A has Rh antigen, his/her blood is said to be A⁺ (A positive). Similarly, if a person’s blood group is B and he/she do not have Rh antigen, then his/her blood group is B^-(B negative). So, we have eight blood groups:

A⁺,B⁺,AB⁺,O⁺,A^-,B^-,AB^- and O^-

The following table gives a complete list of blood group matching:

Blood groups	Donor (can donate to)	Recipient (can take from )
A⁺	A⁺,AB⁺	A⁺,A^-,O⁺O^-
O⁺	A⁺,B⁺,AB⁺,O⁺	O⁺,O^-
B⁺	B⁺,AB⁺,AB^-	B⁺,B-,O⁺,O^-
AB⁺	AB⁺	Everyone (hence called universal recipient)
A^-	A⁺,A^-,AB⁺,AB^-	A^-,O^-
B^-	B⁺,B^-,AB⁺,AB^-	B^-,O^-
O^-	Everyone (hence called universal donor)	O^-
AB^-	AB⁺,AB^-	AB^-,A^-,B^-,O^-