Transfusion Medicine - Krafts Flashcards
What determines a blood group?
The antigens on the red cell surface.
Antigens are inherited how?
Mendelian pattern (everyone has 2 genes - one from mom and one from dad)
Type A Blood
Have A Antigen
Type B Blood
Have B Antigen
Type AB Blood
Have A and B Antigens
Type O Blood
Have neither A nor B Antigens
How do you make antigens?
Start with protein precursor
Add fucose to make H antigen
Add N-Acetylgalactosamine to H antigen to make the A antigen
Add Galactose to H antigen to make B antigen
If you don’t make then antigen, then what?
Then you naturally make antibodies against the antigen.
What gene does almost everyone have?
H Gene, codes for enzyme that makes H antigen
True/False: O has no gene product.
True
Bombay Phenotype
Do not have H antigen, therefore makes antibodies against H, A, and B.
Anti-A antibodies lyse what cells?
Type A Red Cells
Anti-B antibodies lyse what cells?
Type B Red Cells
What antigen is the most important in the Rh system?
D Antigen
Rh factor has 2 alleles: D and d. What antigen is considered Rh+?
D allele = D antigen = Rh+
Rh factor antibodies must be…
ACQUIRED
To make anti-D antibodies, you must:
- Lack the D-antigen on your red cells
2. Get exposed to D+ blood
Antibodies to antigens in the “other” systems are acquired, but how?
- Patient with multiple blood transfusions
2. Patient with multiple pregnancies
Why do we not have blood (components) products rather than whole blood?
- Don’t expose patients to excess antigens
2. Conserve the blood supply
What is apheresis and what is it used for?
Take blood out, take what cells you need, put blood back into patient
Used for platelets and granulocytes
Whole blood can be divided into what 3 blood products?
Red Cells
Granulocytes
Platelet-Rich Plasma
Red Cells can be divided into what 2 blood products?
Leukocyte-Reduced Red Cells
Frozen Red Cells
Platelet-Rich Plasma can be divided into what 2 blood products?
Platelets
Fresh Frozen Plasma
Fresh Frozen Plasma can be divided into?
Cryoprecipitate
VIII, IX, Albumin, IgG
What does whole blood contain and what is it used for?
RBC, WBC, platelets, plasma
Use: Massive Hemorrhage
What does Red Cells contain and what is it used for?
RBC!!!
Few WBC, platelets, plasma
Use: Low Hemoglobin
What does Leukocyte-Reduced Red Cells contain and what is it used for?
RBC!!!
NO WBC, Rare platelets, little plasma
Use: Low Alloimmunization
Low Allergic Reactions
What does Frozen Red Cells contain and what is it used for?
RBC and few WBC
Use: Storage of rare blood types (good for 10 years)
What does Granulocytes contain and what is it used for?
Neutrophils
Use: sepsis in neutropenic patients
What are platelets used for?
Bleeding due to Thrombocytopenia
What does Fresh Frozen Plasma contain and what is it used for?
Plasma (including ALL coagulation factors)
Use: Bleeding due to multiple factor deficiencies (Disseminated Intervascular Coagulation)
What does Cyroprecipitate contain and what is it used for?
Fibrinogen, von Willebrand factor, VIII, XIII
Use: Low fibrinogen, vW disease, Hemophilia A, XIII deficiency
What is VIII used for?
Hemophilia A
What is IX used for?
Hemophilia B
What is Albumin used for?
Hypovolemia with Hypoproteinemia
What is IvIG used for?
Disease prophylaxis, autoimmune disease, immune deficiency states
Forward Type
Add anti-A, anti-B, anti-D antibodies to red cells
DAT (Direct-Antiglobulin Test) using Anti-humanglobulin to cause agglutination if positive
Reverse Type
Add B-Type RBCs to patient serum with anti-B antibody
DAT using AHG to cause agglutination if positive
Add A-Type RBCs to patient serum with anti-A antibody
DAT using AHG to cause agglutination if positive
Crossmatch
Add donor RBCs to patient serum
DAT using AHG - if positive, do NOT give that blood to patient
Antibody Screen
Multiple Pregnancies or MultipleTransfusions
Look for antibodies in the patient against weird blood groups
Add “weird reagent” RBC to patient serum, perform DAT with AHG to cause agglutination if positive (looking for antibodies in the patient’s serum)
Acute Hemolytic Transfusion Reactions
Due to ABO antibody mismatch against donor red cells
Symptoms: fever, chest pain, hypotension, kidney pain
Hemoglobin in serum and urine
Labs: Decreased Haptoglobin, Increased Bilirubin, DAT positive
Delayed Hemolytic Transfusion Reactions
Due to Rh antibody mismatch causing extravascular hemolysis occurring days after transfusion, with a falling hemoglobin
Labs: DAT positive, Antibody Screen
Febrile Transfusion Reactions
Commonly caused by recipient antibodies against WBC in donor blood which causes a febrile reaction with fever, headache, nausea, chest pain (all induced by cytokines)
Treatment: Tylenol; Leukocyte-reduced components
Allergic Transfusion Reactions
Host reaction to donor plasma proteins which results in hives
Treat with antihistamines
Rarely causes anaphylaxis
What do you do if you suspect a transfusion reaction?
STOP THE TRANSFUSION
Check blood of patient and donor
Monitor vitals
Send blood, urine, and bag of blood to lab
Transfusion-related bacterial infections
Symptoms: Fever, shock
Treatment: aggressive resuscitation and antibiotic therapy
Test: patient and blood unit
Circulatory Overload
When too much blood is given too quickly
Symptoms: hypertension, CHF
Treatment: Stop transfusion, give diuretics
Iron Overload
Too much iron can damage the heart and liver (High risk: chronic anemia)
Treatment: Iron-Chelating agents
Graft vs. Host Disease
Donor lymphocytes attack host in immunocompromised patients or blood-relative donors
Symptoms: fever, rash, hepatitis, marrow failure, usually fatal
What is the most common infection from a blood transfusion?
Bacterial Infection (more common in platelets = stored at room temperature, than in RBC transfusions = stored in fridge)
What is the least common infection from a blood transfusion?
Hepatitis C and HIV
What is the most common complication from a blood transfusion?
Allergic Reaction
What is the least common complication from a blood transfusion?
Acute Hemolysis
