Pre-test Flashcards
What are the reagents used in an antibody screen?
screening cells, LISS, and check cells
What type of patient specimen is used in an antibody screen?
patient serum or plasma
What is the purpose of the DAT?
Useful in detecting HDN, HTR, and AIHA
What are the components of a DAT?
AHG and patient cells
If an Rh control tube is necessary in the Rh testing, and it is positive, the interpretation of the Rh type is _______.
invalid
What are the two types of AHG that can be used in blood banking?
Broad spectrum/polyspecific and monospecific
Describe broad spectrum/polyspecific.
contains both anti-complement (C3d) and anti-IgG
Describe monospecific.
contains either anti-complement (C3d) or anti IgG
What is the purpose of the IAT?
detects antibodies or complement attached to RBCs in vitro
What are the components of the IAT?
patient serum and screening cells
What are two blood bank procedures that incorporate the IAT?
compatibility testing for donor cells and antibody screen
What are two tubes included in Du testing?
D test and Rh control
What are the steps for Du testing?
- incubate tubes at 37C for 15 min
- Using saline, wash cells 3 times
- Mix 2 drops AHG to each tube, centrifuge on high for 15 seconds
- Add 1 drop check cells to non-reactive tubes
In the fetal bleed screening test, the presence of agglutinated cells indicates that the maternal blood contains possibly a significant number of________.
Rh positive fetal cells
What term is used to describe the agglutination that constitutes a positive fetal bleed screening test?
rosette
What is the quantitative test performed when a fetal bleed screening test is positive?
Kleihauer-Betke test
Who does the AABB require have the fetal bleed screening test performed?
Rh = mothers who deliver an Rh + baby
What is another situation that may require a fetal bleed screening test?
abortion
What are four conditions that the DAT can detect?
HDN, HTR, AIHA, and drug induced RBC sensitization
What are the two components of an auto control?
patient red cells and patient serum
What are the components of a crossmatch?
recipient plasma and donor RBCs
Two cell populations in a patient specimen can produce what type of agglutination?
mixed-field agglutination
What are the components of a forward ABO grouping?
anti-A and anti-B antisera and patient cells
What are the components of a reverse ABO grouping?
patient serum and A1 and B cells
What can be done to enhance an ABO reaction that is very weak upon immediate spin?
sit at RT for 30 min or incubate at 4C
What blood bank procedure is used to resolve a positive DAT?
elution
What blood bank procedure is used to resolve a positive antibody screen?
perform antibody panel to identify antibodies present
Describe clinically significant antibodies.
IgG which react at 37C and in the AHG phase
In a pregnant female, what antibody class is clinically significant?
Rh
What is the Rh antibody class the most clinically significant in a pregnant female?
if a mother is Rh+ and baby is Rh= HDN could occur
What are the two AABB requirements for routine crossmatching tests?
demonstrate ABO compatibility and clinically significant antibodies
Why is the washing procedure before the addition of AHG so important?
to prevent neutralization of AHG by globulins present in blood
FFP of the AB group is compatible with what blood group recipients?
all blood groups
If check cells are added to a negative AHG tube, and after centrifugation agglutination is not seen, give two possible explanations.
inactive AHG or neutralized AHG
What must be done if agglutination is not seen after addition of check cells to a negative AHG tube?
panel must be repeated
