Compatibility testing Flashcards
major crossmatch
patient serum + donor cells
minor crossmatc
donor serum + patient cells
not done after 1970s
crossmatch today
serves as a double check of ABO errors & clinically significant Ab
compatibility testing vs crossmatch
compatibility includes crossmatch! also includes: accurate recipient ID sample collection & handling required pre-transfusion testing process begins w/ the transfusion requires & ends w/ the transfusion of blood product to patient
crossmatch testing
mix donor cells & recipient plasma IS & read add potentiator 37 incubate & read wash 3x add AHG & read
crossmatch testing interpretation
compatible or incompatible (doctor needs to override in order to use incompatible blood)
Regulatory organizations
AABB: american association of blood banks
FDA
3 types of crossmatch
immediate spin crossmatch- IS
computer crossmatch
Antiglobulin XM
usage of IS crossmatch
when there is no evidence of Ab in current sample or past history
usage of AHG XM
when patient has current or past clinically significant antibody
will be positive if unit had positive DAT
usage of computer XM
only when recipient dose not have clinically significant Ab in current or past samples
XM limitations
viral transmission, allergic or febrile reactions
cannot detect all antigens, especially low frequency ones
Kidd antibody could be extremely low titer
1 unit of packed RBCs should increase Hct/Hgb by :
3% Hct or 1g/dL Hgb
Pretransfusion testing: specimen collection
samples for pretransfusion testing can be used for 3 days (day of collection is day 0)
no serum separators
must be retained by blood bank ~7-10 days
special specimen collection procedure for 30 day specimen
pertains only to ppl undergoin a surgery within 30 days & have not had a transfusion/pregnant in the last 3 months
previous record review
all past clinically significant Ab are to be honored regardless of results of Ab screen &/or ID in current specimen
selection of compatible blood products
ABO identical when possible
if >2mL of RBCs, donor RBC must be ABO compatible with recipient
ABO Ab in transfused plasma should be ABO compatible w/ patient
special considerations for infants <4 months
initial compatibility testing includes ABO & D typing
any antibody screen can use the mother’s specimen
can use satellite bags
Emergency release of uncrossmatched blood
physician must sign request
units are tagged indicating uncrossmatched
emergency situation: patient w/ unknown blood type
O units are issued: Rh pos for males & Rh neg for females
% of recipients receiving uncrossmatched blood have an immediate intravascular transfusion reaction?
«<1%
needs preformed complement binding antibody
what % of recipients receiving uncrossmatched blood develop a clinically significant Ab?
1-3%
Massive transfusion
total blood volume exchange through transfusion during a 24 hr period
serologic testing may be temporarily suspended
Autologous blood
donated by the patient for themselves, usually for an elective surgery
if not used, it must be discarded bc it is not held to the same standards as normally donated blood
Fresh frozen plasma
must be ABO compatible!
Rh is not a factor
platelet concentrate (5% of plt transfusion)
minimum of 5.5x10^10 plts
ABO does NOT have to be compatible
remain rotating at RT & expires in 5 days
pheresis platelets (>95% of transfusions)
minimum of 3x10^11 plts
does not have to be ABO compatible
rh is not a factor
remain rotating at RT & expires in 5 days
cyroprecipitate
rich in factor VIII, vWF, FXIII, Fibrinogen
‘fibrin glue’
must remain at RT after thawing
expires 4 hrs after pooling
granulocyte concentrates
minimum of 1x10^10 granulocytes
must be crossmatched & ABO/Rh compatible
must be given within 24 hrs after collection
