Immunohematology Flashcards
What is the the study of immunohematology?
Study of antigen-antibody reactions in the blood
What are antigens?
Anything that prompts the immune system to form antibodies
What is the purpose of antigens on RBCs?
Related to cellular integrity or function
What are the three types of antibodies that transfusion medicine is concerned with?
IgM
IgA
IgG
What does it mean when blood bankers classify antibodies based on clinical significance?
Does it cause hemolytic transfusion reactions
What does it mean when blood bankers classify antibodies/antigens based on source of sensitization?
Natural or immune
What does it mean when blood bankers classify antibodies on class?
IgM or IgG
What does it mean when blood bankers classify antibodies based on allo vs auto?
Non-self or self
What does it mean when blood bankers classify antibodies on optimal temp?
Warm vs cold
What are the three things that carb antigens react in?
Cell adhesion
Malignancy
Infectious disease
What type of molecule are H, A, and B antigens?
carb
What are the two types of Lewis antigen? What type of chemical is this?
Le^s and Le^b
Carb
What class of antibodies do red cell antigens tend to stimulate?
IgM
Do carb antigens span the RBC membrane? Do proteins?
Proteins yes, carbs no
What type of chemical are Rh antigens?
Protein
What type of chemical are duffy, kidd, and kell antigens?
Proteins
What class of antibodies do proteins antigens tend to stimulate?
IgG
What class of antibody does glycophorin A stimulate? Is this serious?
IgM
No
What class of antibody does glycophorin B stimulate?
IgG
Yes
What are the antibodies that are responsible for intravascular hemolytic anemia? Extravascular?
Intra = IgM Extra = IgG
How do IgM antibodies kill targeted foreign RBCs
MAC complex
How are IgG antibodies stimulated to kill RBCs?
Consumed by phagocytes, stimulate immune system
Do IgM antibodies cross the placenta? IgG?
IgM no
IgG yes
Does the Lewis antigen cause hemolytic disease of the newborn? Why or why not?
No, because not expressed until later in life
What are the most important blood groups for transfusion?
ABO
What must be taken into account when transfusing someone?
RBC antigens and plasma antibodies
What is the H antigen on RBCs?
Antigen that is present on 99.9% of all RBCs
What is the phenotype of people who lack the H antigen?
Bombay phenotype
What is the chemical structure of the H antigen?
alpha1 -> 2fucose
What is the only way to change your RBC phenotype?
Bone marrow transplant
ABO antigens develop around what week of development? What percent is found relative to adult life?
6th week
50%
How long does it take to reach adult levels of ab?
3 yo
True or false: whatever ABO antigen you lack, you automatically develop antibodies to
True
What class of antibodies are anti-ABO antibodies?
IgM
True or false: ABO antibodies weaken with age
True
Rh + patients have what antigen?
D
What class are the antibodies against ABO antigen?
IgG
What are the other major Rh system antigens besides D?
C
E
DCe- R1 antigens are common among which ethnicity?
Caucasians
Dce -Ro antigens are common among which ethnicity?
African americans
dce- r antigens are common among which ethnicity?
Rh negative
True or false: d antigen indicates Rh -
False
Is Rh - = Rh 0?
No
Is the D antigen AD or AR?
AD–85% of population has it
What is the antibody that is involved in HDFM?
IgG
What is the classic example of HDFN?
Mom (gravid 2+) is D negative, baby is D positive
When is RhoGAM administered?
28 weeks and once again after delivery
What is in RhoGAM?
Anti-D Abs (passive immunity to D)
What is the indirect Coombs test?
Add pts serum to donor RBCs and look for abs with antihuman antibodies
What is the direct Coombs test?
Add pts RBCs to donor serum, add antihuman abs
Can the Coombs test detect complement?
yes
What is involved in compatibility testing?
Antibody screen for ABO, Rh, or ABO/D
Donor RBCs and pt plasma
