Blood Groups and Transfusions *

Osmosis

What is a blood transfusion?

Procedure where a person receives blood or blood components via intravenous infusion

How are blood components separated?

By centrifugation

What happens during centrifugation?

Heaviest components go to bottom lightest to top

What are the three layers after centrifugation?

Erythrocytes buffy coat plasma

What is in the bottom layer?

Erythrocytes

What is in the buffy coat?

Platelets and leukocytes

What is in the top layer?

Plasma

When is whole blood transfusion used?

Rarely such as traumatic injuries

What is the most common type of transfusion?

Component transfusion

Who receives packed red blood cells?

Patients with anemia

Who receives fresh frozen plasma?

Patients with clotting factor deficiencies

Who receives platelet transfusions?

Patients with platelet deficiencies

What is a homologous transfusion?

Blood from an anonymous donor

What is an autologous transfusion?

Patient receives their own previously stored blood

Why is sodium citrate added to collected blood?

Prevents coagulation

How is donated blood stored?

Refrigerated frozen or separated into components

What must be done before transfusion of RBCs?

Blood typing and crossmatching

What determines a persons blood type?

ABO system and Rh system

What are blood group antigens?

Glycoproteins on RBC surface

Why are blood group antigens important?

They can trigger immune responses if recognized as foreign

What happens if incompatible blood is transfused?

Immune system attacks donor RBCs

What antibodies are involved in ABO reactions?

IgM antibodies

How do IgM antibodies cause damage?

Bind multiple RBCs causing agglutination and activate complement

What is complement activation?

Formation of membrane attack complex leading to RBC lysis

What is a hemolytic transfusion reaction?

Destruction of donor RBCs due to immune response

What symptoms occur in hemolytic transfusion reaction?

Fever hypotension rash

What does the ABO system classify?

Presence of A and B antigens on RBCs

What are the four ABO blood types?

A B AB O

What antibodies do type A individuals have?

Anti B antibodies

What antibodies do type B individuals have?

Anti A antibodies

What antibodies do type AB individuals have?

None

What antibodies do type O individuals have?

Anti A and Anti B antibodies

Who are universal recipients?

Type AB individuals

Why are AB individuals universal recipients?

They lack anti A and anti B antibodies

Why are AB individuals poor donors?

They have both A and B antigens

Who are universal donors?

Type O individuals

Why are O individuals universal donors?

They lack A and B antigens

Why can type O individuals not receive other blood types?

They have both anti A and anti B antibodies

What is the Rh system?

Blood group based on Rh antigen presence

What does Rh positive mean?

Rh antigen present

What does Rh negative mean?

Rh antigen absent

Who can Rh positive individuals receive blood from?

Both Rh positive and Rh negative donors

Why is Rh negative receiving Rh positive dangerous?

Can lead to hemolytic transfusion reaction

Why can Rh positive blood sometimes be given to Rh negative in emergencies?

No preformed antibodies initially

What happens after Rh exposure in Rh negative individuals?

They develop antibodies for future reactions

What test is used to determine ABO type?

Blood typing with anti A and anti B serum

What indicates agglutination in blood typing?

Presence of corresponding antigen

Example of blood typing interpretation?

Agglutination with anti A only means type A

How is Rh status determined?

Using anti Rh serum

How are blood types reported?

ABO type followed by Rh positive or negative

How many total blood types exist?

Eight A+ A- B+ B- AB+ AB- O+ O-

What is crossmatching?

Mixing recipient serum with donor blood

What does agglutination in crossmatch mean?

Incompatibility donor blood cannot be used

Why is crossmatching important?

Detects reactions beyond ABO and Rh systems

What is the function of erythrocytes in transfusion?

Deliver oxygen

What are antigens?

Glycoproteins on RBCs that trigger immune response

What determines antibody formation?

Absence of corresponding antigen in host

What happens if blood is not properly typed?

Hemolytic transfusion reaction may occur

What is the key principle of transfusion compatibility?

Avoid antigen antibody reactions

What blood type is universal donor for RBCs?

O negative

What blood type can donate to all Rh positive recipients?

O positive

What blood type is universal recipient?

AB positive

What blood type can receive from all Rh negative donors?

AB negative

What is the overall purpose of blood typing?

Ensure safe transfusion and prevent immune reactions