AHG

Question 1

DAT

Answer 1

detects RBCs coated w/ Ab/ C’
in vivo

Question 2

IAT

Answer 2

detects non-agglutinating Ab in serum
in vitro

Question 3

Antibody and complement are what type of protein?

Answer 3

globulins

Question 4

monospecific AHG-
anti-IgG

Answer 4

Ab to IgG (gamma chain)

Question 5

monospecific AHG anti-IgG will NOT detect cold reactive Ab that fix complement
true or false

Answer 5

true

Question 6

monospecific AHG- anti-C3d/C3b

Answer 6

contains Ab to human complement

Question 7

monospecific AHG anti-C3d has IgG activity
true or false

Answer 7

false- it has no anti-IgG activity and is not used in routing testing (used in investigating positive DATs

Question 8

2 mechanisms of C’ binding in vivo

Answer 8

Ag-Ab complexes bind C’
immune complexes activate C’

Question 9

common C’ binding antibodies

Answer 9

Anti-A
anti-B
anti-JKa
anti-Lea

Question 10

what part of AHG reacts with Fc part of antibody molecule to form a lattice

Answer 10

Fab

Question 11

why must cells be thoroughly washed before adding AHG?

Answer 11

to prevent neutralization of AHG reagent

Question 12

all negative AHG reactions must be observed…

Answer 12

microscopically

Question 13

room temperature detects what type of antibodies?

Answer 13

cold antibodies IgM

Question 14

AHG acts as a bridge for what type of cells?

Answer 14

non-agglutinated but sensitized cells

Question 15

37*C enhanced and incubated detects what type of antibodies

Answer 15

warm antibodies IgG

Question 16

factors affecting IAT testing

Answer 16

temperature
ionic strength
reagents
proportion of serum to cells
time of incubation

Question 17

applications of IAT testing

Answer 17

prenatal testing
pre transfusion testing
compatibility testing (crossmatch)
antibody ID and titers
RBC phenotyping

Question 18

sources of error DAT/IAT testing false negatives

Answer 18

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

Question 19

sources of error DAT/IAT testing false positives

Answer 19

agglutinated RBCs
containers
dirty glassware
over centrifugation
AHG reagent

Question 20

sources of error DAT testing false negatives

Answer 20

low # attached antibodies
complement binding

Question 21

sources of error DAT testing false positives

Answer 21

use of serum samples
gel separator tubes
samples from IV lines
septicemia

Question 22

sources of error IAT testing false negatives

Answer 22

sample storage
plasma samples
temperature and incubation time
cell suspension

Question 23

sources of error IAT testing false positives

Answer 23

cells coated w/ IgG (positive DAT)