Transfusion Medicine Flashcards
two components of blood?
cellular elements (RBC, WBC, plts)
plasma (soluble proteins and Abs)
Blood type A
A antigen
Ab B in plasma
Blot type B
B antigen
Ab A in plasma
Blood type AB
AB antigens
NO abs in plasma
Blood type O
No antigens on RBC
Abs to A and B
Universal donor
type O
Universal recipient?
type AB
There are over ___ RBC group systems and ___ blood group antigens
29
250
How are RBCs broken down?
- Complement activation
- Activation of phagocytic cells
- activation of coagulation
- systemic inflammation
- scavenge NO (free Hgb)
Where are ABO Ags found? Are they soluble?
membrane bound
YES!
What are other locations that ABO blood group antigens are found?
– Red cells and platelets
– Vascular endothelium
– Epithelial surfaces
What are soluble forms of ABO blood group antigens?
saliva, milk, urine, meconium, feces
What reactions are caused by ABO blood system incompatibilities?
- Hemolytic transfusion reactions (IgM)
- Solid organ transplantation (hyperacute rejection)
- Mild hemolytic disease fetus and newborn
What is mild hemolytic disease of the fetus/newborn?
- mom is group O and baby is A, B or AB
- small percentage of IgG Abs cross placenta and hemolyze fetus’ RBCs
What clinical sxs are assocaited with ABO incompatible RBC transfusions? What is the MC presenting symptom?
– Feelingofdread – Flushing – Feverandchills – Pain at infusion site, lumbar spine and flanks – Chestandabdominalpain – Nausea, vomiting – Shock – Dyspnea, hyperventilation, cyanosis
FEVER IS THE MOST COMMON PRESENTING SYMPTOM!!!
What is the most important antigen associated with the Rh group?
D antigen (interchangable with Rh)
What is the most immunogenic blood group outside ABO?
Rh
Ab formation to Rh requires exposure to antigen
How are antibodies to D antigen (Rh) formed?
IgG Abs form AFTER exposure >
cause extravascular hemolysis
Can IgG Abs cross the placenta? What does this lead to?
YES
hemolyitic disease of the newborn
How do you prevent hemolytic disease of the newborn?
anti-D prophylaxis with RhoGAM or Win RHO
Before RhoGAM ppx:
– D antigen responsible for most cases of HDFN
– 100% fatal for fetus
What clinical sxs are assocaited with increasing hemolysis from Anti‐D or anti‐ABO antibodies?
– Anemia
– Tachycardia
– Increased rate of blood flow
What is the difference between weak D and partial D?
- Weak D: Lower levels of D antigen on surface of RBC
* Partial D: Some antigens not present, causing negative screening results
When are weak and partial D results (essential giving a false negative D Ag test) important?
Donor center
OB pts