Transfusion Medicine Flashcards
What are these symptoms indicative of?
- Heat along arm & under armpits
- Varied pulse, sweaty face
- Great pain in kidneys
- Sick to stomach
- Lie down, fell asleep and slept all night
- Black urine in the morning
Transfusion Reaction!
What determines a blood group?
The antigens on the RBC surface
What is interesting about Red Cell Antigens?
- Antigens are inherited (mendelian pattern)
- Real function unknown
- Damn important during transfusion
- Lots of antigens exist (grouped into systems)
- Most important systems: ABO and Rh
What different combinations of antigens can RBCs have (in ABO system)?
- Some ppl have A antigen (type A)
- Some ppl have B antigen (type B)
- Some ppl have both A and B (type AB)
- Some ppl have neither (type O)
How do you make antigens?
- Start with a protein precursor
- Add fucos to make H antigen
- Add N-acetylgalactosamine to H Ag to make A Ag
- Add galactose to H Ag to make B Ag
What are the genes related to RBC antigens?
- H gene
- A, B, and O genes
What’s interesting about H gene?
- Almost everyone (except bombay phenotype!) has this one
- It codes for an enzyme that makes H antigen
What are the possible genotypes with A, B and O genes?
- Everyone has two genes
- Six possible genotypes: AA, BB, AB, AO, BO, OO
- A and B code for ENZYMES that make A and B antigens
- O has no gene product
What is the Bombay phenotype?
- These people don’t make A, B or H antigens (like special O types)
- They don’t have H gene which is bad for transfusions since they make antibodies then for H gene on all RBCs
- Very difficult to get transfusions, can only get from another “bombay” type - can be frozen and stored
How common is each blood type?
A - 40%
B - 12%
AB - 6%
O - 42%
Why are blood types important?
You need to know what antibodies each person has. We all have antibodies to the types of antigens we don’t have!
What is it bad for the patients blood to have antibodies to the donor but not for the donors blood to have antibodies to the patient?
- It doesn’t matter if you put antibodies to the patient blood type in the patient.
- THESE ANTIBODIES DON’T REALLY REACT, but we really don’t want to put red blood cells in the patient that the patient has developed antibodies toward
What blood types can donate to AB?
AB, A, B, O
What blood types can donate to O?
O
What are the Rh system antigens?
- Most important antigen = D
- “Rh” because discovered using Rhesus monkeys
- “Rh factor” refers to the D antigen
- Two alleles: D and d
- People with the D allele make D antigen and are Rh +
What is unique about the antibodies in the Rh system?
- Antibodies are ACQUIRED!
- To make anti-D you must:
1. Lack the D antigen on your red cells
2. Get exposed to D+ blood - Donor and recipient are tested for the D antigen
What are other systems for blood grouping?
- There are a shitload of other systems
- These aren’t included in routine testing
- Antibodies & antigens in these systems are usually acquired (like anti-D), so unless a patient has been transfused or pregnant, you don’t need to worry about too much.
What is the blood product granulocyte referring to?
Essentially just neutrophils
What is Apheresis donation?
- Take blood out, run it through machine and machine takes out what ever you need and then puts the rest back into the patient
- Can get a lot of platelets out of a donor this way without them having symptoms
What are the three main branches of blood products?
From whole blood you can make:
- Red cells
- Granulocytes
- Platelet-Rich Plasma
What two things can you make from Red Cells?
- Leukocyte-Reduced Red Cells
2. Frozen Red Cells
What two things can you make form Platelet-Rich Plasma?
- Platelets
2. Fresh/Frozen Plasma
What is in Fresh/Frozen Plasma?
-Cryoprecipitate Coagulation Factors: -VIII -IV -Albumin -IgG