MIDTERM LABORATORY L2: ANTI-HUMAN GLOBULIN TEST Flashcards
(34 cards)
Direct antiglobulin test is aka
direct Coomb’s test
purpose of direct Coomb’s test
detection of autoantibodies
difference between direct and indirect Coomb’s test
direct-> in vivo
indirect-> in vitro sensitization of RBC with IgG and complement
applications of direct coomb’s test
1) detection of incomplete antibodies to potential donor RBCs
2) screening cells in serum determination
3) titration of incomplete antibodies
define direct antiglobulin test
detects in-vivo sensitization of RBC
define indirect antiglobulin test
detects in-vitro sensitization of RBC
why is Coomb’s test necessary
some antigen-antibody reactions react only up to sensitization phase, cannot form lattice formation-> unconfirmed leads to lattice formation in the body-> complement activation->potential hemolytic transfusion reaction
anti-human globulin is specific to what antibody type
IgG or complement
what bridges the sensitized rbc to visualize lattice formation
IgG or complement
DAT is significant for
detection of autoantibodies of px against their own red cells
IAT is significant for
detection of unexpected antibodies (aside from anti-A and anti-B) in a patient’s serum that may react with donor red blood cells.
interpret:
presence of agglutination in DAT
DAT positive
in DAT, hemolysis indicates positive or negative result?
positive result
what is the strongest reaction in hemagglutination reaction
hemolysis
interpret:
absence of agglutination in DAT
DAT negative
what is the step required to confirm DAT negative result
adding of QC cell or check cells
interpret:
presence of agglutination in IAT
IAT positive
positive IAT indicates
presence of atypical antibodies in px serum coating red cells in vitro
interpret:
absence of agglutination in IAT
IAT negative
IAT is useful in what tests
1) detecting weak-D antigens
2) red cell phenotyping
3) antibody screening and id
4) minor crossmatching
how many IgG or C3 molecules bound per cell are required for detection by antiglobulin antibodies
200-500 IgG or C3 molecules per cell
T or F:
negative result by AHG reagent exclude the possible presence of antibodies because of its high sensitivity
F
although sensitive, it does no exclude the possibility
AHG reagent that contains both anti-IgG and anti C3d
Polyspecific
AHG reagent that contains either anti-IgG or anti-C3d
Monospecific
