Blood transfusion
BLOOD GROUPS
There are a total of 23 blood group systems and a total of over 400 diifferent individually recognized antigenic differences. Some of the blood group systems (e.g. ABO, Rh, Kell, Duffy and Kidd) are recognized to be more clinically important than others, i.e. in relation to transfusion and /or pregnancy.
The ABO and RhD blood groups are so clinically important as to require prospective testing and matching prior to transfusion.
ABO Blood Groups and ABO Typing
The blood group substances are generally determined and inherited as Mendelian characteristics. There are three allelic genes (A, B and O) that determine four blood groups: group O, genotype OO, group A, genotypes AA and AO, group B, genotypes BB, BO and AB, genotype AB. Depending on which blood antigen is on the red blood cell. The reciprocal antibody is found in the plasma (serum). The groups are named according to the antigen present on the red cell. The serum always contains the isoagglutinins for which there are no corresponding agglutiniogens in the red cells.
Blood Group Antigens:
There are composed of:
Major (ABO and Rh) which are of high clinical importance.
Minor (MNSs, P, Lewis, Lutheran, Kell, Kidd, Duffy, Ii…..) which are relatively of low clinical importance (in multi-transfused patients, the corresponding antibodies are potential causes of reactions in subsequent transfusion).
Pubic antigens (Vel, Gerbich, Lan); are of very high incidence i.e. present in almost all individuals.
Private antigens (Wright a and Berrens a) are of very low incidence.
ABO Blood Grouping:
The following two tests should be made:
Determination of cell group by testing red cells with antisera of known type.
Determination of serum group by testing serum with red cells of known type.
Rh Blood group System:
Rh system is the most complex system in terms of number of antigens, relationship among antigens and nomenclature proposed by different investigators.
Basic Rh System:
Basic information is derived from 5 antisera: anti-Rho (D), anti-Rh (C), anti-rh’’ (E), anti-hr’ (C) and anti-hr’’ (C).
The Rh antibodies:
They differ from those of the ABO system in lacking naturally occurring antibodies.
They are immune in origin, which few exceptions (anti- Cw & anti-E).
Usually IgG.
They are of clinical importance in recipients, pregnant women and donors.
Blood Donor Selection:
Donor’s age should be 20 – 60 years old. Fasting of 3 to 4 hours. Body weight more than 50 kg.
None of the following should be present: Anemia, malaria, Syphilis, Viral hepatitis, Brucellosis, coronary artery disease, Sever hypertension, Active T.B, Rheumatic fever, Diabetes mellitus, Pregnancy, Infections, Bleeding tendency, Allergies, Immunizations or AIDS, Blood pressure and Pulse rate should be within normal.
Blood Collection:
Blood is obtained under sterile conditions by phlebotomy and is collected in plastic bags that contain about 63 ml of CPD for 21 days storage or 70 ml CPDA-1 up to 35 days.
Cross matching:
The purpose is to detect any possible incompatibility between the recipient’s serum and the donor’s red cells (major cross match) and between the donor’s serum and the recipient’s erythrocytes (minor cross match) that might lead to a transfusion reaction.
An incompatible cross match is recognized by agglutination or lysis of the donor’s or the recipient’s red cells at any phase of the cross match. An incompatible recipient, an error in the identification of the specimen, or atypical antibodies in either donor or recipient blood.
The cross match is preceded by the serologic tests necessary to type ABO, Rh and any other factor that appears to be indicated in the donor and the recipient.
Screening of donor and recipient for atypical antibodies is not a substitute for the cross matches that uncovers errors in the ABO typing which screening fails to do.
Screening does not replace the minor cross match when O blood is administered to AB patients since the minor cross match will always be incompatible.
ABO and Rh type-specific blood compatible by all cross matching procedures should be chosen.
The Universal Donor:
Group O blood should only be used for group O recipients. In emergencies, for exchange transfusion in the newborn infant, and if the patient’s group cannot be ascertained, group O blood may be issued, provided that there is no high-titre antibody present. Low titre O blood may be issued to A or B recipients, but it should not be given to group AB individuals. Generally, O blood is considered safe if the titre of both isoagglutins is less than 1: 50. Group O Rh-negative red cells should be used when the patient’s blood is unknown.
Transfusion Reactions:
The untoward reactions occurring during a transfusion or shortly afterwards and does not include the long-term deleterious effects as the transmission of hepatitis or the immediate results as acute congestive heart failure.
Whenever a transfusion reaction occurs, the transfusion must be discontinued at once. Transfusion reactions can be divided into hemolytic and non-hemolytic.
1- Non-hemolytic Reactions include:
Allergic reaction: the most common and the least severe reaction. It may be due to some soluble substance in donor plasma. Antihistaminics and cortisone should not be added to the blood, but rather administered to the patient directly.
Febrile reactions: the use of disposable equipment and strict adherence to blood bank regulations eliminate febrile reactions. Some reactions may be due to antileukocyte or antiplatelet antibodies. Infusion of cytokines performed by leucocytes in the donor stored blood or provocation of cytokine release in the recipient may lead to reactions.
Bacterial reactions: the bacteria are usually gram-negative bacilli. The patient’s reaction is often severe and anaphylactoid in nature or characterized by profuse bleeding.
2- Hemolytic Reactions:
The most serious, are due to the destruction of red blood cells (donor) by antibodies in the plasma of the recipient. The severity of the reaction will depend on the amount of blood transfused, the type and avidity of the antibody. In a patient under anesthesia, unexplained oozing from the operative wound may be the first sign of a reaction.
There are some hemolytic transfusion reactions that are latent or delayed, other reactions are nevertheless due to an antigen-antibody reaction. Serious hemolytic transfusion reaction result in hemoglobinemia, methemoglobinemia, hemoglobinuria, hyperbilirubinemia (3 – 6 hours after transfusion).
Dangers of Transfusion:
a- After a single transfusion:
1- Transfusion reactions.
2- Overloading of circulation due to speed or excessive volume of transfusion.
3- Temporary arrest of erythropoiesis.
4- Formation of immune antibodies to red cells, white cells, platelets and / or clot factors.
5- Thrombophlebitis.
6- Transmission of disease e.g. hepatitis, malaria, infectious, mononucleosis (syphilis can not be transmitted by stored blood) and AIDS.
7- Hemosiderosis and post transfusional hemochromatosis.
b- During Massive Transfusion:
1- Fall in level of clotting factors (fibrinogen, calcium, platelets).
2- Increase in anticoagulants (heparin, fibrinolysins).
3- Increase in potassium as donor’s cells release their potassium.
4- Citrate toxicity and fall in ionized calcium.
5- Overloading of circulation.
Indication for direct coomb’s test:
1- Diagnosis of erythroblastosis foetalis.
2- Diagnosis of autoimmune hemolytic anemias.
3- Diagnosis of transfusion reaction due to incompatible blood.
Indication for Indirect coomb’s test:
Cross matching to detect incompatibility.
Detection and identification of irregular antibodies.
Detection of antigens such as Rh, Kell, Duffy and Kidd.
There are a total of 23 blood group systems and a total of over 400 diifferent individually recognized antigenic differences. Some of the blood group systems (e.g. ABO, Rh, Kell, Duffy and Kidd) are recognized to be more clinically important than others, i.e. in relation to transfusion and /or pregnancy.
The ABO and RhD blood groups are so clinically important as to require prospective testing and matching prior to transfusion.
ABO Blood Groups and ABO Typing
The blood group substances are generally determined and inherited as Mendelian characteristics. There are three allelic genes (A, B and O) that determine four blood groups: group O, genotype OO, group A, genotypes AA and AO, group B, genotypes BB, BO and AB, genotype AB. Depending on which blood antigen is on the red blood cell. The reciprocal antibody is found in the plasma (serum). The groups are named according to the antigen present on the red cell. The serum always contains the isoagglutinins for which there are no corresponding agglutiniogens in the red cells.
Blood Group Antigens:
There are composed of:
Major (ABO and Rh) which are of high clinical importance.
Minor (MNSs, P, Lewis, Lutheran, Kell, Kidd, Duffy, Ii…..) which are relatively of low clinical importance (in multi-transfused patients, the corresponding antibodies are potential causes of reactions in subsequent transfusion).
Pubic antigens (Vel, Gerbich, Lan); are of very high incidence i.e. present in almost all individuals.
Private antigens (Wright a and Berrens a) are of very low incidence.
ABO Blood Grouping:
The following two tests should be made:
Determination of cell group by testing red cells with antisera of known type.
Determination of serum group by testing serum with red cells of known type.
Rh Blood group System:
Rh system is the most complex system in terms of number of antigens, relationship among antigens and nomenclature proposed by different investigators.
Basic Rh System:
Basic information is derived from 5 antisera: anti-Rho (D), anti-Rh (C), anti-rh’’ (E), anti-hr’ (C) and anti-hr’’ (C).
The Rh antibodies:
They differ from those of the ABO system in lacking naturally occurring antibodies.
They are immune in origin, which few exceptions (anti- Cw & anti-E).
Usually IgG.
They are of clinical importance in recipients, pregnant women and donors.
Blood Donor Selection:
Donor’s age should be 20 – 60 years old. Fasting of 3 to 4 hours. Body weight more than 50 kg.
None of the following should be present: Anemia, malaria, Syphilis, Viral hepatitis, Brucellosis, coronary artery disease, Sever hypertension, Active T.B, Rheumatic fever, Diabetes mellitus, Pregnancy, Infections, Bleeding tendency, Allergies, Immunizations or AIDS, Blood pressure and Pulse rate should be within normal.
Blood Collection:
Blood is obtained under sterile conditions by phlebotomy and is collected in plastic bags that contain about 63 ml of CPD for 21 days storage or 70 ml CPDA-1 up to 35 days.
Cross matching:
The purpose is to detect any possible incompatibility between the recipient’s serum and the donor’s red cells (major cross match) and between the donor’s serum and the recipient’s erythrocytes (minor cross match) that might lead to a transfusion reaction.
An incompatible cross match is recognized by agglutination or lysis of the donor’s or the recipient’s red cells at any phase of the cross match. An incompatible recipient, an error in the identification of the specimen, or atypical antibodies in either donor or recipient blood.
The cross match is preceded by the serologic tests necessary to type ABO, Rh and any other factor that appears to be indicated in the donor and the recipient.
Screening of donor and recipient for atypical antibodies is not a substitute for the cross matches that uncovers errors in the ABO typing which screening fails to do.
Screening does not replace the minor cross match when O blood is administered to AB patients since the minor cross match will always be incompatible.
ABO and Rh type-specific blood compatible by all cross matching procedures should be chosen.
The Universal Donor:
Group O blood should only be used for group O recipients. In emergencies, for exchange transfusion in the newborn infant, and if the patient’s group cannot be ascertained, group O blood may be issued, provided that there is no high-titre antibody present. Low titre O blood may be issued to A or B recipients, but it should not be given to group AB individuals. Generally, O blood is considered safe if the titre of both isoagglutins is less than 1: 50. Group O Rh-negative red cells should be used when the patient’s blood is unknown.
Transfusion Reactions:
The untoward reactions occurring during a transfusion or shortly afterwards and does not include the long-term deleterious effects as the transmission of hepatitis or the immediate results as acute congestive heart failure.
Whenever a transfusion reaction occurs, the transfusion must be discontinued at once. Transfusion reactions can be divided into hemolytic and non-hemolytic.
1- Non-hemolytic Reactions include:
Allergic reaction: the most common and the least severe reaction. It may be due to some soluble substance in donor plasma. Antihistaminics and cortisone should not be added to the blood, but rather administered to the patient directly.
Febrile reactions: the use of disposable equipment and strict adherence to blood bank regulations eliminate febrile reactions. Some reactions may be due to antileukocyte or antiplatelet antibodies. Infusion of cytokines performed by leucocytes in the donor stored blood or provocation of cytokine release in the recipient may lead to reactions.
Bacterial reactions: the bacteria are usually gram-negative bacilli. The patient’s reaction is often severe and anaphylactoid in nature or characterized by profuse bleeding.
2- Hemolytic Reactions:
The most serious, are due to the destruction of red blood cells (donor) by antibodies in the plasma of the recipient. The severity of the reaction will depend on the amount of blood transfused, the type and avidity of the antibody. In a patient under anesthesia, unexplained oozing from the operative wound may be the first sign of a reaction.
There are some hemolytic transfusion reactions that are latent or delayed, other reactions are nevertheless due to an antigen-antibody reaction. Serious hemolytic transfusion reaction result in hemoglobinemia, methemoglobinemia, hemoglobinuria, hyperbilirubinemia (3 – 6 hours after transfusion).
Dangers of Transfusion:
a- After a single transfusion:
1- Transfusion reactions.
2- Overloading of circulation due to speed or excessive volume of transfusion.
3- Temporary arrest of erythropoiesis.
4- Formation of immune antibodies to red cells, white cells, platelets and / or clot factors.
5- Thrombophlebitis.
6- Transmission of disease e.g. hepatitis, malaria, infectious, mononucleosis (syphilis can not be transmitted by stored blood) and AIDS.
7- Hemosiderosis and post transfusional hemochromatosis.
b- During Massive Transfusion:
1- Fall in level of clotting factors (fibrinogen, calcium, platelets).
2- Increase in anticoagulants (heparin, fibrinolysins).
3- Increase in potassium as donor’s cells release their potassium.
4- Citrate toxicity and fall in ionized calcium.
5- Overloading of circulation.
Indication for direct coomb’s test:
1- Diagnosis of erythroblastosis foetalis.
2- Diagnosis of autoimmune hemolytic anemias.
3- Diagnosis of transfusion reaction due to incompatible blood.
Indication for Indirect coomb’s test:
Cross matching to detect incompatibility.
Detection and identification of irregular antibodies.
Detection of antigens such as Rh, Kell, Duffy and Kidd.
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