Blood Group Immunology

Question 1

What are the 2 antiglobulin tests?

Answer 1

IAT/DAT

Question 2

Who receives whole blood?

Answer 2

Pts who need Volume and cells

Question 3

How do packed cells help pts who need red cells?

Answer 3

1 unit increases HCT by 3% and Hgb 1 g/dl

Question 4

What is an antibody?

Answer 4

: serum protein that is induced by, and reacts specifically with a foreign substance (Ab)

Question 5

What is an antigen?

Answer 5

foreign substance that induces an immune response by causing production of antibodies and or sensitized lymphocytes that react specifically with that substance(Ag

Question 6

How is a persons blood grp antigen inherited?

Answer 6

Individuals inherit a gene which codes for specific sugar(s) to be added to the red cell.
The type of sugar added determines the blood group.

Question 7

What blood type do you give in an emergency?

Answer 7

Type O negative

Question 8

What does a blood grp refer to?

Answer 8

antigenic properties of blood constituents

Question 9

What are the antigenic properties of blood constituents?

Answer 9

Red blood cell antigens
White blood cell antigens
Platelet antigens
Plasma protein antigens

Question 10

What is the most rare blood type?

Answer 10

AB

Question 11

What is the clinical significance of blood antibodies?

Answer 11

ABO antibodies are immune and will result in destroying incompatible cells . Never transfer an antigen to someone with corresponding antibody

Question 12

What immunoglobulin is responsible for hemolytic transfusion rxn?

Answer 12

IgM

Question 13

Describe transfusion rxn?

Answer 13

Most severe with ABO mismatches.Rapid intravascular hemolysis.Free Hgb is releasd to the plasma. Severity also related to the amount of RBCs given

Question 14

What are symptoms of a major HTR?

Answer 14

Fever, Chills, Backache, Headaches,Apprehension

Dyspnea, Hypotension, Vascular collapse

Question 15

What are possible complications of HTR?

Answer 15

DIC, acute renal failure

Question 16

How do you treat HTR?

Answer 16

if suspected stop transfusion, draw sample of blood and look for Hemoglobenimia(pink plasma)
Vigorously hydrate the patient
Forced diuresis with Manitol may help prevent renal damage

Question 17

What are symptoms of anaphylactic transfusion rxn?

Answer 17

Urticaria and bronchospasm

Due to plasma proteins most of the time

Question 18

What is the pathogenesis of anaphylactic transfusion rxn?

Answer 18

IgA deficient patients, may have anti-IgA and develop reactions to the IgA dissolved in the plasma (transfusion)

Question 19

What happens if blood is contaminated and how do you treat it?

Answer 19

Occurs with gram negative bacteria. Rare. Septicemia and shock from endotoxins. If suspected, culture the blood unit and treat patient with antibiotics

Question 20

Describe Grp O blood

Answer 20

No A or B antigens present, think of as “0” antigens present.These individuals form potent anti-A and anti-B antibodies. UNIVERSAL DONOR

Question 21

Describe Grp A blood

Answer 21

No B antigens present.

These individuals form potent anti-B antibodies

Question 22

Describe Grp B blood

Answer 22

No A antigens present.

These individuals form potent anti-A antibodies

Question 23

Describe Grp AB blood

Answer 23

Both A and B antigens present.
These individuals possess no ABO antibodies.
Their blood does not react against any other ABO type.UNIVERSAL RECIPIENT

Question 24

What Ag do we test for with Rh blood grp?

Answer 24

D Ag, most antigenic

Question 25

Describe Rh antibodies

Answer 25

Produced by a D negative person who has been sensitized or immunized (“exposed”) to the D Ag Can occur during pregnancy or after blood transfusion. Anti-D is an IgG

Question 26

What happens if a Rh negative women is pregnant and baby is Rh positive?

Answer 26

the antibody can cross the placenta and destroy Rh (D) positive fetal cells resulting in death.

Question 27

What is genotype of Rh negative?

Answer 27

dd

Question 28

What is hemolytic disease of the newborn?

Answer 28

Abs from the mother enter the fetal circulation and destroys fetal red blood cells. During pregnancy or at birth (feto-maternal hemorrhage), mother becomes exposed to fetal RBCs and develops Anti-D

Question 29

What causes hemolytic disease of newborn?

Answer 29

Caused primarily by maternal Anti-D recognizing D Ag in fetal RBCs.

Question 30

What is the pathogenesis of hemolytic disease of newborn?

Answer 30

During pregnancy or at birth (feto-maternal hemorrhage), mother becomes exposed to fetal RBCs and develops Anti-D. Anti-D is a monomer can cross the placenta. affects subsequent pregnancies

Question 31

What are mild symptoms of hemolytic newborn disease?

Answer 31

mild anemia, jaundice, or breathing problems detected at birth

Question 32

What are severe symptoms of hemolytic newborn disease?

Answer 32

heart failure, brain damage, stillbirth or miscarriage

Question 33

How do you prevent hemolytic newborn disease?

Answer 33

with Rh immune globulin (RhIG) given to the Rh negative mothers. screen fathers

Question 34

What is rhogam and what does it do?

Answer 34

Anti-D antibody (RhoGAM) provides a “passive immunization" to the fetus by suppressing mother's immune system from attacking it

Question 35

When is Rhogam not needed?

Answer 35

If the father is absolutely known to be Rh(-);

Question 36

When is Rhogam given?

Answer 36

to D negative mothers at 28 Wks and 72hrs after delivery of a D-positive baby. Also given after miscarriage, abortion or amniocentesis. Repeated every pregnancy

Question 37

Why do anti-A and anti-B antibodies not cross the placenta?

Answer 37

because these immunoglobulins are IgM

Question 38

What is the antihuman globulin test (coomb's test)?

Answer 38

Uses a commercial antibody against human globulin (AHG) to detect globulin coated RBCs Also used for Hemolytic conditions

Question 39

How does testing for blood grp antigens work?

Answer 39

Patients RBCs are combined with known antiserum (antibodies) commercially available, observing for agglutination. If the Ag present on the cells correspond to the antibody in the reagent, Ab will bind to the Ag and cause clumping of the cells (agglutination)

Question 40

What is in whole blood?

Answer 40

450ml blood and 63 ml anticoagulant, Hct 40%

Question 41

What is whole blood not a good source of?

Answer 41

platelets, factor V or VIII

Question 42

What is in packed cells?

Answer 42

RBCs

Question 43

When is FFP given?

Answer 43

for multiple factors deficiency

Question 44

What is in cryo?

Answer 44

factor VIII, XIII, fibrinogen, vWF, fibronectin