9. laboratory tests
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Definition
Series of testingprocedures and processes
To ensure the bestpossible results of a bloodtransfusion
Cannot guarantee RBCviability
Cannot totally eliminatetransfusion reactions
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Pre-transfusion testing
ID, collection & prep ofsamples
Donor sample:
By collecting facility: ABO &Rh grouping, diseasetransmission, antibody ID if w/possible sensi.
By transfusing facility: confirmABO & Rh using attachedsegment
Patient sample:
ABO & Rh, antibody screening
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Crossmatching
Importance ofSerologicXmatch:
1. Final ABO compatibilitycheck
2. Antibody against untestedAg
Can be eliminated if(a.k.a. Type & Screen):
1. No clinically significant
antibodies were detected
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Serologic Crossmatch
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Serologic Crossmatch
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Crossmatching
Computer Crossmatch
Emergency Crossmatch
Abbreviated Incomplete crossmatch
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Other considerations
Non ABO specifictransfusion
Plasma products
Intrauterine transfusions Neonatal transfusions
Massive transfusions
Specimens with prolongedCT
Autologous transfusion
Effective blood utilization
Reidentification of atient
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Definition
Red cells that areagglutinated by a largeproportion of adult human
sera regardless of bloodgroup.
Usually non-reactive with
autologous serum
Acquired or inherited
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Categories
Microbial associated(Transient, common)
T, Tk, Acquired-B, Th, VA
Non-microbial associated(permanent & irreversible)
Tn, CAD, NOR
HEMPAS (hereditaryerythroblasticmultinuclearity w/ a positive
acidified serum) a chronic
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Laboratory Testing
Detection
Not easily detected:
Natural polyagglutinins are
destroyed during themanufacturing process
Antibodies are low in titer
Apparent duringcrossmatching (esp minor)
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Laboratory Testing
Confirmation
RBC should be tested withseveral cord blood sera and
with several normal groupAB adult sera
Classification
Enzymes Lectins
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Laboratory Testing
Absorption
Enzymes
Cord sera Aged sera
Dilution
Sulfhydril compounds Absorption & elution
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Adsorption
Removal of antibody fromserum by absorption withred cells of appropriate
phenotype
Useful in:
Removal of unwanted
antibody (e.g. Autoantibody,interference with reagent)
Separation of multiple
antibodies
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Elution
Release of antibodymolecules from red cellmembrane
Done by disruptingantigen or by changingconditions to favordissociation of Ag-ab
Common methods: Heat technique (Landsteiner
& Miller)
Ether technique (Rubin)
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HemeagglutinationInhibition
To demonstrate presenceof soluble substance inbody fluids
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Neutralization
To inactivate unwantedantibodies
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Panel Cell Testing
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Definition
Quantification of antibodypresent
Performed when the ff arenot available:
Flow cytometry
Radioimmunoassay
ELISA