21- An Introduction to Transfusion Medicine Flashcards
What are the requirements to be able to donate blood? How much blood is taken and how frequently can you donate whole blood?
age>16 yrs
pass a limited history/physical (questionnaire, general appearance POC, BP, Hb)
donation for whole blood= 8 week intervals
apporx 500 ml of blood is taken
How do we manufacture a blood product?
Centrifugation! We separate Cells from plasma
What 9 diseases do we test blood products for?
Syphillis
Hepatitis B
Hepatitis C
HIV
HTLV-I/II
West Nile Virus
Trypanosoma cruzi
Zika Virus
Babesia microti
What antigen(s) and antibodies does group A blood have?
A antigen (on RBC)
Anti-B antibody (in plasma)
What antigen(s) and antibodies does group B blood have?
B antigen (on RBC)
Anti-A antibody (plasma)
What antigen(s) and antibodies does group AB blood have?
A and B antigen (on RBC)
No antibodies!
What antigen(s) and antibodies does group O blood have?
No antigens! (on RBC)
Anti-A antibody and Anti-B antibody , Anti-AB antibody
(I have never heard of anti-AB antibody but I put it on here bc it was on this picture, not sure if it is real. but what do I know I’m not a doctor)
How important is the ABO red cell blood group system?
When do people develop their antibodies?
Most important red cell blood group system!
Antibodies are naturally occuring, very potent, and can activate complement
(responsible for many acute/fatal hemolytic transfusion reactions)
What is the most important antigen for Rh blood typing? When do people develop antibody?
You either have the Rh antigen (D antigen) (+) or you don’t (-)
D is immunogneic-80% sensitization
antibodies develop thorugh pregnancy or trans fusion (aka exposure)
implicated in hemolytic disease of the newborn and hemolytic transfusion reactions
Pre-transfusion testing can be “type and screen” or “type and cross” what thing do we type and screen for?
ABO and Rh
Antibody screen
low likelyhood for transfusion ie pre-op for cholecystectomy
Pre-transfusion testing can be “type and screen” or “type and cross” what thing do we type and cross for?
ABO and Rh
Antibody Screen
Cross Match
Moderate to high likelyhood for transfusion likelihood (ie pre-op heart surgery)
What is done for pre-transfusion testing? Write out the path if the antibody screen was negative
Patient blood sample
perform ABO/D typing
perform antibody screen ***negative**
select ABO/D compatible product
perform cross-match
issue RBC product
What is done for pre-transfusion testing? Write out the path if the antibody screen was positive
Patient blood sample
perform ABO/D typiing
Perform antibody screen (unexpected antibodies) **positive**
perform antibody identification panel
Select ABO/D compatible, antigen-negative RBC product
perform cross-match
issue RBC product
How do we test for ABO?
Add in A, B and AB cells to the patients plasma/serum and see what clumps
clumping signals that the patient has antibody against whatever cell type was added
What is the IAT Antiglobulin Test (IAT)? Screen
The IAT detects red cell antibodies in the patient’s serum
(we are adding known cells to the patients serum and looking for response)
uses: antibody screen/panel, compatibility testing
What do you do if the IAT antibody screen is positive?
an antibody identification panel (another bigger IAT)
What is crossmatch?
- Another IAT
- Final test: is the blood that we selested for your patient?
- units are screened for antigen if Abs identified (via the IAT)
- confirmation/Ab specificity not ID’d on AB screen
- crossmatch may be omitted under certain circumstances
so add in donor cells to the patient’s serum. these are not the same cells from the IAT, these are cells from a volunteer that we don’t know a lot about
What does the DAT detect? What are 4 causes?
antibody attached to patient red cells in vivo
Autoimmune Hemolytic Anemia
Drug Induced Hemolytic Anemia
Hemolytic Transfusion Reactions
Hemolytic DIsease of Newborn
(we add atibodies to patient whole blood)
Why is it important to plan ahead for pre-transfusion testing?
It can take an hour! and that is if nothing is found on the IAT!
You need to get one of these every 3 days while transfusions are needed
What does emergency release blood mean?
skips all the steps to get you blood fast!
uncrossmatched
red cells=O (mostly pos), plasma=ABA/A
What does Massive support mean?
Friends like Drs. Pook and Matter <3 but also…
helpful at times of severe, uncontrolled bleeding
uses emergency blood components in a ratio to prevent coagulopathy
10RBCs/6plasma/1plt, or 6 RBCs/6plasma/1plt
What blood products can you get?
Red blood cells (RBCs)
Plasma (FFP)
Platelets (Plts)
Cryoprecipitate (Cryo)
(aldo whole blood and granulocytes)
How do we prep and store RBCs? What do they contain? what is their outcome?
Prep: Cells separated by centrifugation, plasma removed, stored at 4C for 42 days
Contains: 300ml, HCT 55-60%, no viable platelets for WBCs
Outcome: transfuse over 3-4hrs, raise Hgb 1g/dl in average size adult
What blood type is the universal recipient and the universal donor?
Donor: O-
Recipient: AB+