AHG Flashcards
DAT
detects RBCs coated w/ Ab/ C’
in vivo
IAT
detects non-agglutinating Ab in serum
in vitro
Antibody and complement are what type of protein?
globulins
monospecific AHG-
anti-IgG
Ab to IgG (gamma chain)
monospecific AHG anti-IgG will NOT detect cold reactive Ab that fix complement
true or false
true
monospecific AHG- anti-C3d/C3b
contains Ab to human complement
monospecific AHG anti-C3d has IgG activity
true or false
false- it has no anti-IgG activity and is not used in routing testing (used in investigating positive DATs
2 mechanisms of C’ binding in vivo
Ag-Ab complexes bind C’
immune complexes activate C’
common C’ binding antibodies
Anti-A
anti-B
anti-JKa
anti-Lea
what part of AHG reacts with Fc part of antibody molecule to form a lattice
Fab
why must cells be thoroughly washed before adding AHG?
to prevent neutralization of AHG reagent
all negative AHG reactions must be observed…
microscopically
room temperature detects what type of antibodies?
cold antibodies IgM
AHG acts as a bridge for what type of cells?
non-agglutinated but sensitized cells
37*C enhanced and incubated detects what type of antibodies
warm antibodies IgG
factors affecting IAT testing
temperature
ionic strength
reagents
proportion of serum to cells
time of incubation
applications of IAT testing
prenatal testing
pre transfusion testing
compatibility testing (crossmatch)
antibody ID and titers
RBC phenotyping
sources of error DAT/IAT testing false negatives
inadequate washing of RBC (#1)
delay of testing
inactive/absent AHG
improper centrifugation
improper strength of cell suspension
prozone
IgG cryoprecipitate
saline pH
check cells
sources of error DAT/IAT testing false positives
agglutinated RBCs
containers
dirty glassware
over centrifugation
AHG reagent
sources of error DAT testing false negatives
low # attached antibodies
complement binding
sources of error DAT testing false positives
use of serum samples
gel separator tubes
samples from IV lines
septicemia
sources of error IAT testing false negatives
sample storage
plasma samples
temperature and incubation time
cell suspension
sources of error IAT testing false positives
cells coated w/ IgG (positive DAT)
