BLOOD GROUPING and clinical relevance.pptx

Blood grouping and clinical imporfance

1. BLOOD GROUPING VICTORIA UNIVERSITY K`PLA BPHARM STUDENTS PRESENTED BY KAWALYA STEVEN

2. Explain The Process Of Blood Typing And Its Clinical Importance In Blood Transfusion Blood typing is a process of classifying blood into several blood groups based on presence or absence of specific antigens on the surface of red blood cells and antibodies in their plasma . The main blood typing systems are ABO system and Rhesus system. Others include; Kidd, Kell , MNS blood group systems.

3. ABO system was discovered in the 1901, by a German immunologist Karl Landsteiner. In his classification of blood groups, He based on observation reaction of agglutination or hemolysis between the antigen on erythrocytes and antibodies present in the serum of individuals when directed against these antigens .

4. KEY DEFINITIONS IN BLOOD GROUIPING Antibodies ; these are serum proteins produced in response to stimulation by a foreign antigen and it is capable of reacting specifically with that antigen in an observable way. Immunoglobulin (agglutinins); of much importance in blood grouping include; Rhesus- Ab are IgG type ABO- Ab are IgM type .

5. ANTISERUM (ANTISERA)

6. Antigen ( agglutinogen ); is any substance which when introduced in to an individual who himself lacks the substance, stimulates the production of a corresponding antibody. When erythrocytes are introduced as foreign substances in the body, they become immunogenic . Agglutination ; this is the clumping of particles with antigens on their surfaces Antiserum ; Is a purified, diluted and standardized solution contain a known antibody which is used to know the presence or absence of antigens on red cells with an importance to phenotype ones blood group. Hemagglutination - occurs when RBCs bind with antibody molecules that form cross linkages/ bridges between antigenic determinants. Here the antigen is referred to as agglutinogen and the antibody as agglutinin, It occurs in two stages;

7. First Stage-Sensitization; Antibodies present in serum become attached to corresponding antigen on the RBC surface. ( RBC which has been coated by antibodies is said to be sensitized). Secondary Stage ; Physical agglutination of sensitized RBCs takes place which is caused by antibody attaching to antigen on more than one red cell producing a net or lattice that holds the cells together. The RBCs form aggregates which if large enough and visible to naked eye .

8. Inheritance of ABO-RBC genes and chemical structure of antigens A and B Blood group is determined by presence of antigens A and B , on RBCs. Every Individual has two chromosomes each carrying either A, B or O as means of allelic genes, inherited one from each parent and thus the possible inherited ABO genotypes are AA or AO, BB or BO, AB and OO. This makes four groups of populations; group A, B, O and AB, where the phenotype and genotype are both AB heterozygous.

9. Development of ABO Antigens

10. Rh Blood System Rhesus blood group system depends on Rhesus factor, an important antigen on the RBCs, inherited almost as one gene. Rh antigens are important proteins in providing the stability of the red cells membrane. RBCs can be either Rh positive ( RhD / Rh+) indicating presence of the Rh antigen or Rh negative ( Rhd / Rh-) for absence of Rh antigen. MNS, Xg , Luther, Kell , Duffy, and Kidd…… Blood Grouping Systems Antigens in these systems may each lead to the development of immune antibodies after an antigen-negative individual is exposed through transfusion or pregnancy. These antibodies at times can cause severe hemolysis.   Clinical significance of Blood Grouping in transfusion Blood Transfusion is a medical procedure in which donated blood is provided to patients through intravenous line. After requisition to transfuse of blood, the blood components are carefully chosen. Blood is donated to patient for therapeutic replacement of the blood components that may be too low;

11. BLOOD COMPONENTS Whole blood is given in treatment of hemorrhagic conditions due to trauma/surgery and postpartum bleeding since they need all components of blood they have lost. Packed red cells given patients with chronic anaemias like Sickel cell disease, heart failure due to anaemia because we do not need to over load the heart. Fresh frozen plasma given in patients with hypovolemia in conditions such as dehydration and severe burns as a volume expander. Cryoprecipitate given to patients that have deficiency in clotting factors (Fibrinogen and F actor VIII) in treatment of Hemophilia A and Von Willebrand disease. Then Factor IX for treatment of Hemophilia B . Platelet concentrates given to prevent bleeding in patients with thrombocytopenia like leukemia, aplastic anemia and non functional platelets .

12. Blood plasma is a yellowish fluid component of blood. Serum is the clear yellowish liquid that remains after a blood clot. (Simply its plasma without clotting factors ) Blood collection Ca2+ clotting activator vacutainer tube EDTA anticoagulant Vacutainer tube

13. ABO and Rh typing are done on donor blood products and to the recipient’s blood to determine their corresponding RBC surface antigens before transfusing

14. Blood typing is used in compatibility testing for safer transfusion Some patients develop immune antibodies in other blood group systems that are clinically significant i.e Non-ABO IgG antibodies e.g Kidd, Xg , Kell , Duffy and MNS antibodies . Cross match/compatibility test is performed to cross-check if the potential donor blood component matches the recipient red cell type . Patient’s serum is mixed with few drops of donor RBCs cells to detect for any other unexpected antibodies that may cause adverse reactions agglutination or hemolysis of donor red cells in the recipient circulation.

15. Antibody screening; commercially prepared RBCs with known antigens, these antigens cause direct production of antibodies leading to hemolytic reactions. Commercially made RBCs are mixed with recipient serum to detect presence of those very antibodies. It is also carried out on plasma concentrates to detect donor plasma antibodies that may react to patient red blood cell. Compatibility helps a patient to receive maximum benefit from transfused red cells which will survive maximally in his circulation . Also prevents fetal hemolytic transfusion reactions where the antibody-antigen reaction causes the affected RBCs to be destroyed. Blood typing is used to detect Rh incompatibility in the pregnant mother and new born . Following lab diagnosis, Exchange transfusion or compatible sedimented red cell transfusing is done as treatment for erythroblastosis fetalis in foetus .

16. TRANSFUSION REACTION

17. Heamolytic Disease of the New Born and Foetus Erythroblastosis Fetalis

18. Heamolytic Disease of t he New Born and Foetus Erythroblastosis Fetalis

19. TREATMENT Anti-D Immunoglobulin (Produced as IgM type) Prevents alloimmunisation by inhibiting Fc-gamma signaling of B cells and preventing B cell activation. Anti-D sensitizes Rh+ cells and destroys them 1 st dose: Given about 28 weeks of gestation. (before exposure to fetal cells) 2 nd dose : Given shortly within 3days (72hrs) after delivery. (After potential exposure to Rh+ Cells from baby at birth) Rx is repeated every pregnancy.

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