blood groups_organized.pdf

BLOOD GROUPS There are many types of antigens on R.B.Cs surfaces, but the most common are two types: (1) ABO system. (2) Rh factor. (1) ABO system: Principle: 1. The surface of the RBCs contains antigens called agglutinogenes which are two types: A&B. 2. The plasma contain immunoglobulins called agg...

BLOOD GROUPS There are many types of antigens on R.B.Cs surfaces, but the most common are two types: (1) ABO system. (2) Rh factor. (1) ABO system: Principle: 1. The surface of the RBCs contains antigens called agglutinogenes which are two types: A&B. 2. The plasma contain immunoglobulins called agglutinins (antibodies to agglutinogenes& are two types  &  α Agglutinin (anti A)  attacks agglutinogen A.  agglutinin (anti B)  attacks agglutinogen B. 1. The blood of any person does not contain an antigen & its corresponding agglutinin, otherwise, agglutination of the person's R.B.Cs would occur by this own plasma agglutinins. 2. The blood groups named according to presence or absence of antigens on the RBCs surfaces and their types as shown in the following table. Blood group A B AB O Agglutinogen on R.B.C's A B A,B ------ Agglutinin in plasma   -----& % of population 42% 9% 3% 46%  Group O: is considered as universal donor : i.e. they can donate their blood to other individuals of any blood group because their R.B.Cs have no agglutinogens on their surfaces. However , they can receive only group O blood because their plasma contains α and β agglutinins. Group AB: is considered universal recipient (i.e. they receive blood from any group as their plasma contain no agglutinins). However, they can donate their blood to group AB individuals only because their R.B.Cs surfaces contain both agglutinogens A & B. (1) Rh factor:  Definition:  They are antigens first discovered on the RBCs of Rhesus monkeys, hence the name Rh.  It was observed that three Rh factors are common Cc, Dd and Ee. D is the most common antigen.  Rh positive individual has Rh agglutinogens in RBCs,represent85% of individuals.  Rh negative individual has no Rh agglutinogens or Rh antibodies. And represent 15% of individuals.  Rh agglutinins are not naturally present in plasma.  Production of Rh antibodies may be evoked in Rh negative individual by: a) Transfusion of Rh+ blood. b) Or by the presence of Rh+ fetus in Rh negative mother. Significance of ABO and Rh : Blood transfusion: To avoid incompatible blood transfusion (Blood typing ) slide agglutination test : Materials: -70% alcohol, sterile pin or lancet -glass slide, mixing sticks -anti-A , anti-B & anti-Rh sera. Methods ABO grouping: -Sterilize the thumb, prick it with sterile pin. -place 1blood drop on each side of the glass slide. -place a drop of anti-A serum on one blood drop & a drop of anti-B serum on the other blood drop & mix both drops well with glass sticks. -observe for occurrence of agglutination (Ag/Ab reaction) as indicated by grainy appearance of blood drop. For example :  In the sample the subject has type A blood. if agglutination occurred with Anti-A test serum  Agglutination reaction is the clumping of red blood cells together due to antigen _antibody reaction and ends by red blood cell hemolysis Regarding to Rh system : -If agglutination occurs with anti-D then it is group Rh + ve. -If no agglutination occurs with anti-D then it is group Rh - ve.