Ag-Ab Testing/Antiglobulin Tests Flashcards
What are the 3 sources of antigens and 3 sources of antibodies? Are they unknown or known?
Antigens = Patient (unknown) Mfg (known) Donor cells (unknown)
Antibodies = same
What is the difference between direct and indirect agglutination?
Direct react directly
Indirect requires crosslinking
What is the principle of the antiglobulin test?
Antihuman antibodies attach to fe portion of sensitizing and form crosslinking and thus agglutination
What antibodies are found in the reagent and when you use polyspecific and Monospecific reagents?
Both are Anti IgG and C
Poly Used as a screen, Mono is used to diff when poly is positive
What are three common blood groups capable of binding complement?
ABO, Lewis and Kidd
What is the composition, purpose, results of check cells?
O pos D+ cells coated with anti-D+ = sensitized
What are the causes of unexpected results of check cells?
Failure to add AHG, Inadequate washing, neutralization of AHG, Cell washer out of saline
What is the purpose of, requirement and steps of IAT?
In vitro binding, requires incubation and plasma/serum from EDTA OR Red
What is the purpose of, requirement and steps of DAT?
In vivo sensitization, does not require incubation, EDTA only
What are the four causes of positive reactions in DAT
Hemolytic disease of the newborn
Transfusion reactions
Autoantibodies
Drugs
What ar ethe siz applications of the IAT?
Antibody screen, compatibility testing, Antigen typing/phenotyping, weak D typing, Antibody identification, antibody titration
False positive or false negative in antihuman globulin test? Over-reading of reactions
Positive
False positive or false negative in antihuman globulin test? inadequate washing before adding AHG
Negative
False positive or false negative in antihuman globulin test? Dirty glassware
Positive
False positive or false negative in antihuman globulin test? Omission of patient serum or AHG present
Negative
Incorrect incubation temperature
Negative
False positive or false negative in antihuman globulin test? Too heavy or too weak of cell suspension
Negative
False positive or false negative in antihuman globulin test? Interruptions or delays in the washing/AHG steps
Negative
False positive or false negative in antihuman globulin test? Neutralization of AHG
Negative
False positive or false negative in antihuman globulin test? Bacterial contamination of AHG
Positive
False positive or false negative in antihuman globulin test? Using cells with a positive DAT
Positive
What is the purpose of the AGT test?
Used to detect antibodies and is interpreted by agglutination or lack there of with certain cells/serums
