compatibility testing Flashcards
most common cause of error in crossmatching
misidentification of the recipient
content of requisition form
patients full name and unique hospital identification number\
age, birthday, name, address, sex and
requesting physician
agglutination or hemolysis means
incompatible sample
example of in vivo hemolytic processes
hemolytic anemia
may cause small fibrin clot to form and may
be difficult to distinguish from true agglutination
plasma
Patients with IV tubing lines:
Extraction should be done below the IV line
Both donor and recipient samples must be stored for
minimum of 7 days
Three phases of crossmatching:
Immediate Spin Phase
Incubation phase or the thermo phase
▪AHG phase or Coomb’s phase
must be performed on a sample of blood taken at the time of
collection from the donor.
- ABO
- Rh typing
- Weak D determination
sample used for testing must be obtained from
attached segment - hermetic seal
These can be performed in advance of or at the same time
as the crossmatch.
ABO, Rh grouping, and antibody screening
If the Rh type of the recipient cannot be determined and
transfusion is essential
Rh negative blood should be given
This test is unnecessary when testing
transfusion recipients
test for weak D
During emergency the only blood you could give is
packed red blood cell
Rh positive patient may receive
Rh positve and Rh negative
objective of the antibody screening test.
to detect clinically significant unexpected antibodies
Presence of unexpected alloantibodies
▪ Allogenic transfusion of RBCs
▪ Pregnancy or transplantation/ organ tissue
transplantation
* Graft-rejection
ANTIBODY SCREENING METHOD
- Tube method
- Gel-tech
- Solid-phase technique
ANTIBODY SCREENING - CROSSMATCHING
o AHG reagent
o Coomb’s check cell
o Sample of choice
REACTION MEDIUM
22% Bovine Albumin
LISS
PEG
gel used in gel technique
dextran acrylamide gel
does not contain any specific reagent
and acts only by its property of trapping
agglutinates
Neutral
use a specific reagent
incorporated into the gel and are useful for
antigen determination.
Specific gel tests
valuable application of the gel
test and may be used for the IAT or the DAT.
AHG test
