Q. Blood Banking Flashcards
What are the 3 main types of blood you can order for transfusion?
Packed RBCs (for anemia)
Platelets (For bleeding/thrombocytopenia)
Plasma (hypovolemia/coagulopathy)
What type of blood is given for a patient that is anemic and hypovolemic?
Whole blood rarely used
Usually give packed RBCs & plasma
Why is blood frozen? Draw backs?
Increases shelf life (important for rare blood types)
WBCs die during storage –> less febrile reactions
Highly washed –> less allergic reactions
More complications
What is leuko-reduced blood? When is it used?
Remove WBC’s –> remove chance for getting infection like CMV, HIV & EBV that reside in WBCs
Used to have the options of asking for leuko-reduced, but now all blood is automatically leuko-reduced
Why is CMV Ab test ordered on blood? What is it testing for? When is it necessary?
Immunosuppressed individuals are susceptible to getting CMV from non-leukoreduced blood (if WBCs nor removed).
If donor has Ab against CMV, probably have CMV –> don’t give that blood to patient
Used to have to order a CMV Ab test (especially for immunosuppressed). However, due to leuko-reduction now being standard, there is no need for ordering this any longer
Advantages of transfusing leuko-reduced blood?
Less risk of infection (microorganisms that hide in WBCs)
Less acute febrile reactions
Less HLA alloimmunization
What is an autologous blood transfusion? When is it used?
When person saves up blood of their own
If going into surgery
What is a directed blood transfusion?
When friend/family member donates blood so you can have it
Why are some blood samples irradiated? When is this necessary?
Kill WBCs –> can’t proliferate and cause transfusion associated GVH
Immunodeficient patients need this
Why are some blood samples washed?
Removes donor plasma –> less risk of TRALI or allergic reaction
Does washing remove WBCs?
No, GVH possible
Does irradiation remove proteins found in plasma?
No
How are platelets usually obtained for transfusion? Why is this needed?
Apherises just removes donors platelets
Would many units of whole blood to get enough platelets for platelet transfusion –> can’t remove all of that blood from a single donor –> would get exposed to multiple donors. With this are exposed to only 1 donor
What type of molecule are ABO blood antigens? What cells express them?
Glycoproteins & glycolipids (carbs attached to lipid or protein)
All cells in the body express ABO antigens
What is the pathway for creating ABO antigens?
Sugar backbone has Fucose sugar added –> becomes H antigen. Process stops for O, because lacks enzymes for either of the next steps
If N-acetyl-galactosidae is added to H –> H becomes A antigen
If D-galactose is added to H –> H becomes B antigen
What is added to carb to create H antigen? Who has the enzymes to do this?
fucose
Everybody not Oh = A, B, AB & regular O
What is added to H antigen to create A antigen? Who has the enzymes to do this?
N-acetyl galactosamine
A & AB
What is added to H antigen to create B antigen? Who has the enzymes to do this?
D-galactose
B & AB
Why do we usually refer to patients as having O blood instead of H blood?
Usually don’t test for H antigen (because deficiency is rare) –> don’t know if have H, just know that don’t have A or B
What is the Bombay phenotyoe? Recessive or dominant?
Oh = hh (No H)
Lack enzyme to add fucrose to carb
Recessive = Hh has enzyme present
What are isohemoglutanins?
Ab against ABO antigens
Why do we have Ab against ABO blood antigens even without being exposed to blood of types other than our own? At what age do we usually have these antibodies?
Carbs in environment very much resemble ABO antigens –> immunity to them sensitizes us against ABO antigens even if our body hasn’t seen them yet
About 6 mo old
What type of antibody is usually created against the ABo blood antigens?
IgM
Why is a mother not sensitized to her babies ABO antigens during the course of the pregnancy?
Anti-blood antigen antibody is IgM which does not cross placenta
People with blood type A have what hemoglutinins? What about B, AB, O & Oh?
A = anti-B B = anti A AB = none O = Anti-A & Anti-B Oh = Anti-A, Anti-B & Anti-H
What blood type is universal donor?
O
Donor RBCs don’t have A or B antigen so anybody can receive
Really Oh is universal as the few people with Oh can’t receive regular O
What donor is universal recipient?
AB
Donor doesn’t have Ab against A or B (tolerant to both cuz have both)
What type of molecules are the Rh antigens? What cells have these?
Proteins
Only RBCs have them
What are the 5 Rh antigen products? Which one is most important and why?
C, c, D, E, e
D, because either have D or have no D (there is not slightly different version of protein like for other genes) –> complete absence is more immunogenic than slightly different products
When refering to somebody as Rh - or +, what antigen are you referring to?
D
A person with dd for Rh gene has what antigen?
Absent for D gene (d = completely absent, not slightly different versions of 2 proteins)
How common is Rh - (dd)?
Rare
Are C/c & E/e dominant, recessive or co-dominant?
Co-dominant
C,c has C & c protein both present
What Rh alleles are on the same gene? Which one is on its own gene?
C/c & E/e are a single gene that is transcribed into one long protein with all 4 allele contributing a portion
RhD is on its own gene and gene product
Which Rh antigens are typed for usually?
Only D (not C or E)
When is there a problem if a mother is Rh - & fetus is Rh +?
First pregnancy is ok
During birth (when placenta ripped off) –> mom is sensitized –>second pregnancy with same antigen make up has problems
Are ABO & Rh antigens only blood antigens that can cause problems?
No there are other minor blood groupings that can cause problems (we don’t need to know the specifics)
We naturally develop Ab against what blood antigens (without being exposed)?
Only ABO
Only one with similar antigens in environment
How do you do Forward Typing of ABO blood group? What do you see with naked eye and what do you see under microscope?
Agglutination Reaction = To test for A antigen add Anti-A IgM. If antigen present of RBC, IgM acts as linker between RBCs –> clump up
Normal by eye is just sheet of blood. Agglutination = clumping & open spaces form
Under microscope are normally open spaces between cells but those spaces get bigger as cells clump together
Main difference between forward type & Reverse Typing of ABO groups?
Forward = detecting antigen on RBCs
Reverse = detecting Anti-antigen in plasma
How do you do reverse Typing of ABO blood group?
Take exogenous RBCs + patients plasma –> is patient has anti-A/B IgM –> links exogenous RBCs together –> clumping
When is forward & reverse ABO typing used?
Always do both & they must match before transfuse blood
Test recipient and donor before transfusion
What blood type is the patient if forward ABO typing has clumping when Anti-A IgM is added?
Patient has A antigen on their RBCs –> Type A
What blood type is a donor if reverse ABO typing shows clumping with the addition of A RBC or B RBCs?
Donor plasma has IgM against A & B antigens –> Donor is type O or OH
How is Rh blood typing determined?
Same as ABO
What is an antibody screen?
Screen plasma for IgM against Rh or minor blood antigens
What tests are done before transfusion takes place?
Type (forward and reverse ABO typing)
Screen (Rh & minor Ab screen)
Done on donor & recipient
Donor and recipient are ABO/Rh compatible & antibody screen was negative. Can you transfuse blood?
Not yet
Must do crossmatch first
What is the next step if patients blood has a positive Ab screen?
Determine which Ab are present
Select donor that does not have that antigen
What is crossmatching?
Recipient RBCs + donor plasma
+ –> clumping or hemolysis –> recipient has Ab against donor RBC antigen
What type of blood is best to give to a patient that is type A?
Best to give A
Can give O, but then will run out of O
A patient that is Rh + can receive blood from what type of donors?
Rh + or -
A patient that is Rh - can receive blood from what type of donors?
Rh - only
What is it called when sensitized (previous exposure) Rh- patient receives Rh+ blood?
Acute Hemolytic Transfusion reaction
What is it called when sensitized (previous exposure) Rh- mother has Rh + fetus?
Hemolytic Disease of Newborn (HDN)
Why are ABO mismatches between mother and fetus not an issue like Rh?
Because ABO IgM can bind to any cell –> diluted out & not concentrated to just RBCs like Rh
What is the pathophysiology if Hemolytic Disease of Newborn (HDN) & clinical presentation?
Hemolysis –> anemia –> extramedullary hematopoesis
Hemolysis –> anemia –> increase CO –> high output CHF –> pulmonary edema –> respiratory distress
Hemolysis –> jaundice
Anascara = full body edema
What is Anascara?
full body edema seen in fetus after HDN
How is Hemolytic Disease of a newborn prevented?
At end of first pregnancy mom given Rhogam –> Anti RhD antiserum –> destroys fetal RBCs before there is a problem –> prevents sensitization –> no problem with next pregnancy
Patient had an abortion or other pregnancy loss where the childs Rh status was not known. What should be done with next pregnancy?
Treat with Rhomgram as if the previous baby was Rh + just in case
What is alloimmunization to HLA?
Platelets (and to a lesser extent) WBCs have HLA antigens
After sensitization –> can have situaiton where donated platelets are destroyed
Should only transfuse HLA compatible blood for platelets
What type of compatibility is really only important to transfusion of platelets?
HLA comparability
What should be suspected when give thrombocytopenic patient platelets but their plt count doesn’t go up? What is this called?
HLA incompatibility where patient has previously been exposed
Platelet Refractoriness
If recipient has Ab against donor RBCs what happens? What is this called?
Hemolysis = Hemolytic Transfusion Reaction
If the recipient has Ab against donor WBC or platelet what happens? What is this called?
Fever = Acute Febrile Non-Hemolytic Reaction
What happens if donor plasma has cytokines present in it? What is this called?
Fever= Acute Febrile Non-Hemolytic Reaction
If the recipient has Ab against the proteins in the donor plasma what happens? What is it called?
Urticaria (hives) = Acute Urticarial reaction
What are the 2 types of Hemolytic Transfusion Reactions?
Acute = < 24 hours Delayed = > 24 hours
How much of a blood transfusion is needed to cause hemolysis?
As little as 50 mL
Why watch patient during first 10 minutes of a transfusion
What type of hemolysis is caused if the recipient has IgG against donor antigen? What about IgM?
IgG –> strong C’ fixation –> intravascular hemoylsis
IgG –> weak C’ fixation –> extravascular hemolysis
IgM –> weak C’ fixation –> intravascular hemolysis
What blood group incompatibilities cause hemoylsis?
ABO, Rh or minor antigens
Hemolysis due to transfusion causes what clinical presentations?
Fever/chills Chest pain/SOB Burning at Infusion site Tachycardia DIC Hypotension Shock Death
What tests are performed after hemolysis occurs?
Redo typing and cross match + do direct coombs
How do you do a Direct Coombs Test for IgG?
Patients blood (with their original RBCs & recently recieved RBCs) + Rabbit Anti-IgG antibody –> links together new RBCs from donor that are coated in IgG –> clumping
How do you do a direct coombs test for IgM?
You don’t. Test for complement instead
How do you do a direct coombs test for C3?
Give rabbit anti C3 Ab –> links together C3 on surface of newly acquired RBCs –> clumping
Ho do you do an indirecr coombs test?
Exogenous RBCs + patients plasma + rabbit anti-Ab –> patients Ab bind exogenous RBc surface & Rabbit ab links together coated RBCs –> clumping
What is another name & abbreviation for direct coombs?
Direct Anti-globin Test = DAT
IAT = indirect coombs
What causes delayed hemolysis? Can it cause disease? Are they DAT +?
Low titer of Ab –> not detected in screening –> takes longer to act
Can be fatal
DAT +
Are patients with Acute Febrile Non-Hemolytic Reactions DAT +?
No
How can you prevent Febrile Non-hemolytic Transfusion reactions?
Leuko-reduced blood
What causes Acute Urticarial Transfusion Reaction?
Recipient has IgE against donor antigen –> allergic symptoms
Are patients with Acute Urticarial Transfusion Reaction DAT +?
No
Clinical presentation of Acute Urticarial Transfusion Reaction?
Hives Itching Bronchospasm Anaphylactic shock Death
Treatment for Acute Urticarial Transfusion Reaction?
Anti-histamines
What happens when donor has Ab against recipient RBCs? Why is this unlikely to occur?
Intravascular and Extravascular Hemolysis of recipient RBCs
Packed RBCs have very little plasma (rarely use whole blood). If going to give large amount of plasma check for compatibility
What happens if donor has Ab against recipient WBCs in a plasma transfusion? Pathophysiology?
TRALI = Transfusion Related Acute Lung Injury
Anti-HLA Ab activates marginated WBCs in lung –> lung injury –> respiratory distress
What happens if donorcytokines presnet in a plasma transfusion? Pathophysiology?
TRALI = Transfusion Related Acute Lung Injury
Cytokines –> activate WBCs in lung –> lung injury
Outcome of TRALI?
5% mortality
Survivors recover in a couple days
Clinical presentation of TRALI?
Acute Respiratory Distress
Fever/Chills
Hypotension
Pulmonary edema
Plasma donations from what type of donors reduce the risk of TRALI?
Males have less HLA sensitization
For hypothetical antigen, if recipient is AB & donor is BB, will the recipient be tolerant to blood they are receiving?
yes
For hypothetical antigen, if recipient is AB & donor is BB, will the donors blood be tolerant of donor tissue it comes into contact with?
No
What is Transfusion graft vs. host disease? How is it prevented?
Transfused blood not tolerant of antigens present in donor
Donor WBCs recognize reciepient as foreign
Irradiate blood before transfusion to kill WBCs
Most common cause of fatality related to transfusions?
TRALI
Most common adverse reaction during transfusion? How common?
Acute Febrile Non-Hemolytic Reaction
Relatively common
