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
What does “whole blood” contain and what do you use it for?
- RBC, WBC, platelets, plasma
- ONLY USED FOR massive hemorrhage
What do “red cells” contain and what do you use it for?
- RBC, a few WBC, a few platelets, a little plasma
- Used for low hemoglobin
What do “Leukocyte-Reduced” red cells contain and what do you use it for?
- RBC, no WBC, rare platelets, a little plasma
- Used for decreasing alloimmunization, and decreasing allergic reactions
What do “frozen red cells” contain and what do you use it for?
- RBC, a few WBC
- Used for storage of rare blood types (usually only maintained for rare blood types)
What do “granulocyte” contain and what do you use it for?
- Neutrophils
- Used for sepsis in neutropenic patients
What do “platelets” contain and what do you use it for?
- Platelets
- Bleeding due to thrombocytopenia - never give if patient is “just bleeding”
What does “fresh frozen plasma” contain and what do you use it for?
- Plasma (including all coagulation factors)
- Bleeding due to multiple factor deficiencies - e.g. DIC
What does “cryoprecipitate” contain and what do you use it for?
- Fibrinogen, von Willebrand factor, VIII, XIII
- Used for low fibrinogen, vW disease, hemophilia A, XIII deficiency
What do you use VIII for?
- Its a particular clotting factor the patient is missing
- Hemophilia A
What do you use IX for?
- Its a particular clotting factor the patient is missing
- Hemophilia B
What is albumin used for?
- Its from the plasma
- Used for hypovolemia with hypoproteinemia
What is IvIG used for?
Disease phophylaxis, autoimmune disease, immune deficiency states
What are the three types of blood testing?
Forward type
Reverse type
Crossmatching
What happens in Forward type blood testing?
- Looking to see what antigens are on the surface of blood cells
- If the AHG binds and clots, this means antibodies have stuck to the RBC (positive result)
- This is how we ‘type’ blood
1. Anti-A & Anti-B antibodies added to patient red cells
2. AHG added to mixture
3. See if it clots = positive result!
What happens in reverse type blood testing?
- Same process as forward typing, except you’re looking for antibodies (not antigens) in the serum of patient
- You do this to double check your work
1. Add reagent red cells (type ) to patient serum with anti- Ab)
2. Add AHG
3. If you see clumping, this means positive result
What happens in crossmatch blood typing?
- Do if you have time - good way to triple check
1. First you but patient serum (abs) with donor RBC
2. Then you add AHG
3. If you see clumping, you cannot put that blood into the patient
What is an antibody screen used for?
- Can look for Abs in patient for weird blood groups (ex: luthern, etc.)
- Use if you have a patient that is starting to have transfusion reactions (due to multiple transfusions or pregnancies)
- By process of elimination, you can rule it down to what type of antigens the patient is producing & what antibodies they have
What happens if you give a patient with Rh (-) blood some Rh (+) blood?
- The first time the patient will be fine but then the patient makes antibodies and can never receive Rh (+) blood again
- First transfusion fine but ruined for all others
- Should be used as last resort
What can go wrong in blood transfusions?
- Transfusion reactions (Hemolytic & Non-hemolytic)
- Infections (don’t need to memorize numbers)
- Circulatory overload
- Iron overload
- Graft-versus-host disease
What is an acute hemolytic transfusion reaction?
- Happens when patient has ABO antibodies against the donor red cells
- Most common reason: Clerical error!
- Symptoms: fever (usually first thing to show up! Want to watch carefully), chest pain, hypotension (may also have flank pain or plain not feel good)
- Hemoglobin in serum, urine
- Labs: Dec. haptoglobin, inc. bilirubin, DAT positive
- Type and crossmatch shoes ABO mismatch
Why should you watch fever closely in a blood transfusion reaction?
It could be the start of acute hemolytic transfusion reaction
What is the most worrisome part of acute hemolytic transfusion reaction?
- Busting open of all the cells and the releasing of cytokines and hemoglobin
- Not only the kidneys are affected, but the entire circulatory system!
What are the delayed hemolytic transfusion reactions?
- Least severe transfusion reaction
- Hemolysis occurs days after transfusion
- Caused by antibodies to non-ABO antigens
- Hemolysis usually extravascular
- Presentation: falling Hgb after transfusion
- Usually not severe/dangerous
- DAT + Antibody screen identifies the antibody
What is the DAT?
Direct Anti-globulin test
-Used to determine if patient made antibody that has attached to transfused RBCs
What are febrile transfusion reactions?
- Caused by recipient antibodies against donor WBCs
- Cytokines –> fever, headache, nausea, chest pain
- Diagnosis: rule out everything else
- Treatment: Tylenol, Leukocyte-reduced components
What are allergic transfusion reactions?
- Probably a host reaction to donor plasma proteins
- Symptom: hives
- Treatment: antihistamines
- Rarely, reaction is severe (anaphylaxis)
What do you do if you suspect a transfusion reaction?
STOP THE TRANSFUSION!!
- Check if right blood went to right patient
- Monitor vitals
- Send blood, urine and bag to blood bank
What does the lab do when you send blood urine and bag back?
- Check paperwork
- Look for hemoglobinuria
- Do a DAT
- Repeat ABO, Rh testing
What information should you know about blood infections caused by transfusion?
- Transfusion-related bactericidal infections are uncommon but serious risk
- Patients = sudden fever & shock
- Patient and blood unit must be tested
- Treatment: aggressive resuscitation and antibiotic therapy
- Donor tests: HIV, HTLV, Hepatitis B and C, syphilis
- Despite testing, these diseases are still transmitted
What are other transmissible infections through blood?
-HIV, HTLV, Hep B and Hep C
Others:
-Viruses (EBV, CMV)
-Parasitic diseases (malaria, lyme disease)
What is circulatory overload?
- Happens when too much blood is given too quickly
- Symptoms: hypertension, congestive heart failure
- Treat: stop infusion, give diuretics
What is iron overload?
- Too much iron can damage heart, liver
- Patients with chronic anemias are at biggest risk
- Give iron-chelating agents
What is Graft vs. Host Disease?
- It can be extremely dangerous!
- Donor LYMPHOCYTES attack host
- Immunocompromised patients, or patients with blood-relative donors. (donor recognizes host as foreign but the host doesn’t recognize the donor as foreign)
- Symptoms: fever, rash, hepatitis, marrow failure
- Usually fatal
- Prevent by irradiating products (lab microwave)
What is the risk of getting an infection??
- BACTERIAL IS MOST COMMON!
- Then Hep B
- Then Hep C
- Least common HIV
What are the risks of other complications?
- Allergic reaction -1:100
- Febrile reaction -1:200
- Circulatory overload -1:3,000
- Delayed hemolysis -1:4,000
- Acute hemolysis -1:20,000
- GVHD - unknown
