EXAM #2: BLOOD GROUPS & COMPATIBILITY TESTING Flashcards
In transfusion medicine, where are antigens?
These are proteins on the RBC
In transfusion medicine, where are antibodies located?
Serum
What classes make-up the majority of antibodies that we are concerned with in transfusion medicine?
IgG and IgM
What is the difference between an allo and an autoantibody?
Allo= non-self Auto= self
What class of antibodies causes severe intravascular hemolysis?
IgM
What class of antibodies causes delayed extravascular hemolysis?
IgG
Which class of antibodies crosses the placenta?
IgG
What blood groups are the most important consideration in transfusion?
ABO
*****ABO mismatch causes intravascular hemolytic transfusion reaction.
What is the Bombay phenotype?
Patients who lack the H-antigen, which is normally present on 99.9% of RBCs
What is group A antigen?
N-Acetyoglactosamine added to H antigen
What is group B antigen?
Galactosamine added to the H antigen
What is AB group antigen?
BOTH N-Acetylgalatosamine and Galactosamine
What is O antigen?
ONLY H antigen
If a patient gets an A gene from Mom, and an O gene from Dad, what is the phenotype?
A
When is the adult level of ABO antigen reached?
3 years
What class are the ABO antibodies?
IgM
What type of antibodies are generated against group O?
Anti-A and Anti-B
What type of antibodies are formed against AB?
Neither
What is the antigens in the Rh system that are of concern?
- “Big D”
- C
- E
What is the typical phenotype of a Caucasian in the Rh system?
DCe
What is the typical phenotype of Black patients in the Rh system?
Dce
What is the Rh negative phenotype?
dce
What is Rh positive and negative referring to?
Presence or absence of D antigen
What class of antibodies is generated against Rh?
IgG
What is HDFN?
Hemolytic Disease of the Fetus and Newborn
- Rh- Mom
- Rh+ baby x2
In the second pregnancy there is an issue.*
What is RhoGAM?
- Synthetic Anti-D is given to a Rh- mother
- Intent is for the Anti-D to attach to baby Rh factor and “conceal” them from the Mom’s immune system
What are the two parts of blood typing?
1) Front-type
2) Back-type
Needs to be agreement on both of these to determine the blood type
What is the DAT looking for?
Antibody or complement attached to RBCs
- IgG class
This is looking at the RBCs*
What is the IAT looking for?
In vitro antibody sensitization
What is compatibility testing?
Test donor plasma and patient blood
