BLOOD GROUPS & Blood types. Objectives: 1. List the various types of blood groups. 2. Understand...

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BLOOD GROUPS & Blood types

Transcript of BLOOD GROUPS & Blood types. Objectives: 1. List the various types of blood groups. 2. Understand...

Page 1: BLOOD GROUPS & Blood types. Objectives: 1. List the various types of blood groups. 2. Understand that the RBC surface antigens A or B, or their absence.

• BLOOD GROUPS

• &

• Blood types

Page 2: BLOOD GROUPS & Blood types. Objectives: 1. List the various types of blood groups. 2. Understand that the RBC surface antigens A or B, or their absence.

• Objectives:

1. List the various types of blood groups.• 2. Understand that the RBC surface antigens A or B, or their absence is responsible for determining the blood groups as A, B AB or O, and that these are genetically determined..• 3. Understand that the plasma contains antibodies of the same name

• 4. Explain why a person having a particular blood group (for example group A) can not have antibody of the same type in the plasma.• 5. Compare the distribution of blood groups in the Omani population with some other populations • 6. Describe the importance of the Rhesus blood group, and understand that humans are also classified as Rh+ve or Rh –ve, and that about 95% of Omanis are Rh +ve.• 7. Define the term Rh incompatibility and understand that fetal RBC get hemolysed in this condition.

• 8. Define the term “Mismatched transfusion”.• 9. Explain the terms blood grouping and cross matching 10. Define the term “transfusion hazards”.•

Page 3: BLOOD GROUPS & Blood types. Objectives: 1. List the various types of blood groups. 2. Understand that the RBC surface antigens A or B, or their absence.

antigens on RBC blood group antibody in plasma

A Type A B

B Type B A

A & B Type AB nil

O (nil) Type O AB

Page 4: BLOOD GROUPS & Blood types. Objectives: 1. List the various types of blood groups. 2. Understand that the RBC surface antigens A or B, or their absence.

Genetic determination of blood groups

• Antigens are genetically determined

• Each gene carries

1. either NO antigen (O)

2. Antigen A

3. Antigen B

Paired genes (one from each parent when they meet will have

i. No antigen + antigen A : Genotype (OA): Blood group A

ii. No antigen + antigen B Genotype (OB) Blood group B

iii. No antigen + No antigen Genotype (OO) Blood group O

iv. Antigen A + antigen B Genotype (AB) Blood group AB

v. Antigen A + antigen A Genotype (AA) Blood group A

vi. Antigen B + antigen B Genotype (BB) Blood group B

Page 5: BLOOD GROUPS & Blood types. Objectives: 1. List the various types of blood groups. 2. Understand that the RBC surface antigens A or B, or their absence.

1. Antibodies: not present at birth.

2. Develop when small amts of antigens A & B enter body as food, in bacteria etc 3. Host develops antibodies to these.

4. Chemically these are Ig G and Ig M imunoglobulins

Page 6: BLOOD GROUPS & Blood types. Objectives: 1. List the various types of blood groups. 2. Understand that the RBC surface antigens A or B, or their absence.

% distribution of Blood groups in Omani & other populations

A B AB O

Rh+ve

OMANI 30 20 5 45 95White Americans

40 11 4 45 85

Indian 21 39 9 31 95

Page 7: BLOOD GROUPS & Blood types. Objectives: 1. List the various types of blood groups. 2. Understand that the RBC surface antigens A or B, or their absence.

• Blood transfusion

1. Typing: blood groups of donor and recipient

Type A cannot be given to B and vice versa

Type O is “universal donor”: no antigen on RBC so no reaction

Type AB : universal recipient: no antibodies

blood

Page 8: BLOOD GROUPS & Blood types. Objectives: 1. List the various types of blood groups. 2. Understand that the RBC surface antigens A or B, or their absence.

Type A group (recipient)Antigen A & antibody B

Type B group (donor)Antigen B & antibody A

+

antibody B of recipient will react with antigen B of donor (agglutination) and cause hemolyis of donor cells butAnti A of donor get too diluted to affect A type cells of Recipient. So recipient cells not affected significantly

Clinical presentation of mismatched transfusion:1. Donor RBCs affected2. Immediate hemolysis : chills rigors, acute renal failure; shock3. Delayed hemolysis: jaundice as macrophages digest the agglutinated RBCs

Page 9: BLOOD GROUPS & Blood types. Objectives: 1. List the various types of blood groups. 2. Understand that the RBC surface antigens A or B, or their absence.

To avoid this mismatch:

Blood grouping and typing is done

1. Drop of recipient blood and donor blood separately mixed with a drop of anti A and anti B2. Observe for agglutination and confirm group typeThen select donor type.

Suppose A is selected as donor for recipient who is type A:

Cross matching is to be done

Donor RBCs + recipient’s serum to ensure that some other antibodies are not present in recipient blood

Page 10: BLOOD GROUPS & Blood types. Objectives: 1. List the various types of blood groups. 2. Understand that the RBC surface antigens A or B, or their absence.

Blood Grouping and typing

Page 11: BLOOD GROUPS & Blood types. Objectives: 1. List the various types of blood groups. 2. Understand that the RBC surface antigens A or B, or their absence.

• Rh blood group (from Rhesus monkey)

• Those with antigen on RBC: Rh+ve 90-95% population is Rh +ve No anti Rh antibodies in plasma

• Those WITHOUT this antigen: Rh –ve. No antibodies in plasma (no spontaneous development of anti Rh)

• Rh -ve given Rh +ve blood: antibodies develop

• Next transfusion of Rh +ve to the same person: anti-bodies destroy RBCs

Page 12: BLOOD GROUPS & Blood types. Objectives: 1. List the various types of blood groups. 2. Understand that the RBC surface antigens A or B, or their absence.

• Hemolytic disease of the new born

• Mother Rh –ve + Father Rh +ve

• Fetus Rh +ve

• Some mixing of mother

and fetal blood at delivery

• Mother develops anti-body

to Rh antigen of fetus• Next pregnanacy: antibody from mother

passes palental barrier and affects RBC of fetus

Hemolytic disease of the new born .Varied severity from mild hemolysis to death

Page 13: BLOOD GROUPS & Blood types. Objectives: 1. List the various types of blood groups. 2. Understand that the RBC surface antigens A or B, or their absence.

• Uncommon blood groups

• M, N, Duffy

• Bombay Blood

• Useful for genetic testing in Forensic Medicine

• Usually titre too low to cause any problems

Page 14: BLOOD GROUPS & Blood types. Objectives: 1. List the various types of blood groups. 2. Understand that the RBC surface antigens A or B, or their absence.

• Summary

• Types of blood groups

• Source of antigens and antibodies

• Blood groups of Omani population vis-à-vis others

• Blood grouping qnd crossmatching

• Effects of mismatched transfusions

• Rh blood group and hemolytic disease of the new born