DAT, IAT, Elution, Crossmatch

Question 1

mono AHG

Answer 1

anti-IgG

Question 2

poly AHG

Answer 2

anti-IgG and anti-C3d

Question 3

polyspecific AHG pro

Answer 3

more sensitive (things below detectable limit)

Question 4

poly AHG con

Answer 4

less specific

Question 5

mono AHG pro

Answer 5

more specific

Question 6

mono AHG con

Answer 6

less sensitive - misses Jka antibodies

Question 7

DAT

Answer 7

polyspecific

Question 8

IAT

Answer 8

detect antibody in patient serum

Question 9

DAT

Answer 9

directly test RBC’s for antibody or complement that has already been formed

Question 10

if DAT +

Answer 10

can cause HDFN, DHTR, autoimmune hemolytic anemia

Question 11

reticuloendothelial system

Answer 11

macrophages in spleen and liver regularly remove and destroy old, damaged RBC’s

AND foreign cells

Question 12

antiglobulin test false negatives

Answer 12

-insufficient washing
-AHG not added immediately after washing
-loss of AHG reactivity
-improper centrifugation
-improper cell suspension

Question 13

antiglobulin test false POSITIVES

Answer 13

-complement fixes at room temp
-collected from line contaminated with dextrose
-cold autoantibody
-contaminates that look like clumping
-fibrin strands
-spinning cells too long

Question 14

most false positives can be observing specimen and cell suspension

Answer 14

without AHG

Question 15

DAT limitations

Answer 15

DAT can be negative if there is complete destruction of RBC’s in an immune hemolytic process (ABO incompatibility)

Question 16

all healthy RBC’s have a small amount

Answer 16

of bound antibody and complement

Question 17

reasons for positive for DAT

Answer 17

HDFN, HTR, autoimmune/ drug induced hemolytic anemia

Question 18

follow up for + DAT

Answer 18

check patient’s history (recent transfusion, new drug)
-DAT but with IgG or C3d
-elution and antibody ID
-RBC phenotyping on patient or transfused unit

Question 19

elution

Answer 19

release, concentrate and purify antibodies bound to RBC’s (end with freed antibody)

Question 20

elution tech

Answer 20

temp dependent– IgG
WASH and resuspend cells in saline or saline and albumin

alter pH
acid elution
organic solvents

Question 21

elution 45

Answer 21

gentle method, RBC’s remain intact

Question 22

elution 56

Answer 22

total elution, allows for antibody ID

Question 23

most critical step of elution

Answer 23

initial wash; remove unbound immunoglobulins

Question 24

elution control

Answer 24

last wash supernatant should be saved and testing in parallel with elute to detect presence of unbound antibody

LAST WASH should be nonreactive otherwise invalid

Question 25

cord blood testing

Answer 25

done on infants of mothers who are group O or D-

Question 26

crossmatching

Answer 26

RBC unit should be tested with compatibilty with recipient plasma

Question 27

plasma units should be selected for compatibility but

Answer 27

require no crossmatch

Question 28

plasma cross match with patient cells

Answer 28

minor crossmatch

Question 29

if a patient has no history of antibody and a negative screen they

Answer 29

only need IS crossmatch

Question 30

if patient has antibody history or positive screen

Answer 30

FULL AHG crossmatch