MIDTERM LECTURE 3: DETECTION AND IDENTIFICATION OF ANTIBODIES Flashcards
significance of detection of antibodies directed against RBC antigens
1) investigates potential hemolytic transfusion reactions and immune hemolytic anemias
2) detect and monitor px who are at risk of delivering infants with HDFN
the detection methods are focused on what kind of antibodies
irregular or unexpected antibodies
what are the unexpected antibodies
1) immune alloantibodies
2) naturally occurring antibodies
3) passively acquired antibodies
4) autoantibodies
5) clinically significant alloantibodies
unexpected antibodies that are produced in response to RBC stimulation through transfusion, transplantation, or pregnancy
immune alloantibodies
unexpected antibodies that are formed as a result of exposure to environmental sources such as pollen, fungus, and bacteria
naturally occurring antibodies
T or F:
naturally occurring alloantibodies are produced without RBC stimulation
T
unexpected antibodies that are produced in one individual and then transmitted to another individual
passively acquired antibodies
how can passively acquired antibodies be transmitted
via
1) plasma-containing blood components
2) derivatives i.e. intravenous immunoglobulin (IVIG)
unexpected antibodies that are directed against antigens expressed on one’s own RBCs
autoantibodies
unexpected antibodies that cause decreased survival of RBCs possessing the target antigen
clinically significant alloantibodies
the presence of what kind of unexpected antibodies can complicate the detection of clinically significant alloantibodies
1) naturally occurring alloantibodies
2) passively acquired antibodies
3) autoantibodies
what immunoglobulin class are clinically significant alloantibodies
IgG
at what phase of IAT does clinically significant alloantibodies react
antihuman globulin (AHG) phase
performed to determine the specificity of the antibody present when an unexpected antibody is detected in the antibody screen
antibody identification panel
percentage of the population that has detectable RBC antibodies
0.2-2%
what requires the use of an antibody screen to detect clinically significant antibodies in allogeneic blood donors and in px as part of pretransfusion compatibility testing
Association for the Advancement of Blood & Biotherapies (AABB)’s Standard for Blood Banks and Transfusion Services
T or F:
antibody screen is an AABB requirement
F
why is antibody screen included in standard prenatal testing for obstetric patients
1) to evaluate risk of HDFN
2) assess the mother’s candidacy for Rh globulin (RhIg) prophylaxis
when can an antibody screen may additionally be performed
evaluating the compatibility of allogeneic HSC and bone marrow donors with the intended transplant recipient
traditional testing method used to detect clinically significant antibodies
IAT performed in a test tube
what are the reagents used to sensitize reagent RBCs with the patient’s antibodies
1) RBC reagents (suspended at 2-5% conc. in a preservative diluent)
2) enhancement reagent
3) AHG reagent
Antibody that reacts in immediate spin phase
cold reacting Ab (IgM)
Antibody that reacts in 37C incubation phase
warm reacting Ab (IgG)
Tube technique order of procedure
A.) 37C incubation phase
B.) Observe agglutination
C.) Observe hemolysis
D.) Grade the reaction
E.) Addition of Coomb’s control cells
F.) Washing phase (3x)
G.) AHG/Coomb’s serum phase
H.) Immediate spin phase
HACBFGED
H.) Immediate spin phase
A.) 37C incubation phase
C.) Observe hemolysis
B.) Observe agglutination
F.) Washing phase (3x)
G.) AHG/Coomb’s serum phase
E.) Addition of Coomb’s control cells
D.) Grade the reaction
