Quiz 10 Flashcards
What is Autoimmune Hemolytic Anemia(AIHA)?
Destruction of RBCs as a result of antibody production
What are the two types of Autoimmune Hemolytic Anemia (AIHA)?
- cold and warm AIHA
- drug-induced AIHA
What do suppressor T cell do?
induce tolerance to self-antigens by inhibiting activity of B cells
What are autoantibodies?
Antibodies directed against an individual’s own RBCs
What results in autoantibody production?
loss of suppressor T cells function
What do autoantibodies react with the most?
high prevalence antigens
T or F, all autoantibodies cause RBC destruction.
False, Some individuals produce an autoantibody that attaches to their RBCs, but does not cause RBC destruction
What is a positive DAT or positive autocontrol indicative of (if the patient has not been transfused in the last 3 months)?
the presence of a WARM autoantibody coating the RBC in vivo
What is a positive DAT or positive autocontrol indicative of, if the patient HAS BEEN transfused in the last 3 months?
alloantibody coating the transfused cells; high prevalence antigen (not their own cells)
What do the column agglutination (Gel) and solid phase methodologies enhance?
the sensitivity in detection of autoantibody coated RBCs, especially with IgG
(easier to detect RBC w/ Autoantibodies)
What type(s) of testing do autoantibodies complicate?
- ABO/Rh
- antibody screen
- crossmatches
(routine blood testing)
What is Compensated anemia?
rate of RBC production nearly equals rate of RBC destruction
What lab results may indicate Compensated anemia?
- reticulocyte count is elevated
- Mild decrease in hemoglobin/hematocrit
What is uncompensated anemia?
RBC destruction rate exceeds RBC production rate
What can appear microscopically, on a peripheral smear, with a uncompensated anemia patient?
polychromasia (reticulocytes) or spherocytes
What lab results may indicate uncompensated anemia?
- Increased MCV (Macrocytosis (reticulocytes))
- Unconjugated bilirubin
- LDH increased
- Haptoglobin markedly decreased
What is the percentage of AIHA cases are…:
1. Warm AIHA
2. Cold AIHA
3. Drug Induced AIHA
- 70%
- 18%
- 12%
At what temperature are BENIGN cold autoantibodies detected?
4C
How do you resolve false positive results due to cold agglutinins?
wash patient RBCs with normal saline at 37°C (pre-warm technique)
What can be used instead of the prewarm technique for resolving cold agglutinins?
Dithiothreitol (DTT)
[breaks down the disulfide bonds]
What will indicate cold agglutinins during blood testing?
extra back type reactions
What is cold agglutinin disease?
The cold autoantibody reacts optimally at 4°C but also reacts above 30°C
Who would most likely have cold agglutinin disease?
patients older than 50 years old