(M) Antibody detection testing Flashcards
Antibodies that are not expected for
the patient to have.
Unexpected/
irregular
antibodies
Type of antibodyes
In ABO, a patient who is type a is
expect to have anti-B
Expected
antibodies
Also known as clinically significant
antibodies. These antibodies are
produced in response to RBC
stimulation and when an individual is
exposed to the foreign RBC antigens.
Immune
alloantibodies
- Antibodies that are present without the
RBC stimulation but probably due to
exposure to environmental sources like
pollen or bacteria (structure similar to
some RBC antigens)
naturally occurring antibodies
- Antibodies that are pre-formed
already in another individual and are
passed onto the other individual. - E.g., Rhogam, which are Rh antibodies
or immunoglobulins that are injected to
a Rh negative mother who just gave
birth to a Rh positive baby. To be able
to neutralize the Rhd antigens present
on the mother’s circulation, these
passively acquired antibodies will now
coat the Rh positive fetal RBCs in the
maternal circulation, thereby
preventing the sensitization of the
mother.
passively acquired antibodies
- Antibodies that are directed against
antigens expressed on their own
RBCs.
autoantibodies
Significance of antibody detection
A critical in pretransfusion compatibility testing to test for _________________–
clinically significant unexpected antibodies
antibody detection testing is a tool for investigating which (3) diseases?
- hemolytic transfusion reaction
- immune hemolytic anemias
- HDFN
at what temperature and phase does clinically significant unexpected antibodies react at?
37C at the AHG testing phase
What is the red cell concentration needed for:
- tube method
- gel method
- 2-5%
- 0.8%
The reagents may come in 2 or 3 vial / cell suspension, ideally the antigen expression should be (homozygous / heterozygous) to enhance the detection of the antibodies
homozygous
Why are homozygous antigens preferred over heterozygous in antibody screening?
There are antibodies that have a dosage effect that heterozygous antigens may not be able to detect
What is the sample used for:
- tube method
- gel method
- solid phase adherence
- serum / plasma
- plasma
- serum / plasma (antibodies)
RBC (antigens)
whaat is the procedure used in the tube method of antibody screening?
IAT
what are the three phases of testing in the tube method?
- immediate spin phase
- 37C phase / thermal phase / protein phase
- AHG phase
What antibody does each phase detect?
a. IgG
b. IgM
c. both
d. neither
- immediate spin phase
- 37C phase
- AHG phase
- b
- a
- d
this phase utilizes potentiator
a. immediate spin phase
b. protein phase
c. both
d. neither
b. protein phase / thermal phase / 37C phase
What is done after getting a negative AHG test result?
check cells / coombs control cells are added
This comes with the purchased known cell reagent, determining which antigen is present in the vial
antigram / antigen sheet
T or F
the Rh phenotype is included in the antigram or antigen sheet
T
T or F
all antigrams may share LAT numbers, making it easier to remember
F (LAT-specific)
What indicates a positive result in antibody screening: tube method
agglutination in any of the tubes
I. When interpreting the result of an antibody screening, all tubes are interpreted separately.
II. Therefore if only one of the tubes, in all phases, has hemolysis or agglutination, it is interpreted as negative
a.only the first statement is true
b. only the second statement is true
c. both statements are true
d. both statements are false
d.
I. When interpreting the result of an antibody screening, all
tubes are interpreted as one.
II. Therefore, if any one of the
tubes, in any phases, has HEMOLYSIS or
AGGLUTINATION, it is interpreted as POSITIVE for
antibody screening.
Tube method
1. What is considered as a STRONG positive reaction in antibody screening?
2. What is the disadvantage of using the tube method in antibody screening?
- hemolysis
- It is subjective as reading may differ from one MT to another