ABO BLOOD GROUP SYSTEM Flashcards
most important of all blood group
ABO blood group system
true or false. ABO blood group system already have antibodies against antigens that are absent from their RBCs.
true
using known sources of commercial antisera (anti-A, anti-B) to detect antigens on an individual’s RBCs
forward typing
detecting ABO antibodies in the patient’s serum by using known reagent RBCs (A1, B cells)
reverse typing
true or false. always drop the RBC first and second clear solutions.
false, clear solutions should be dropped first before the RBCs
anti-A reagent color and IG class
blue, IgM
anti-B reagent color and IG class
yellow, IgM
most common blood type
O
true or false. reverse typing before 3 to 6 months of age are considered valid
false, because some or all of the antibodies present may be IgG maternal antibodies that have crossed the placenta
genes that produce specific glycosyltransferases to form ABH antigens
ABO, Hh, and Se
precursor structure on which A and B antigens are made
H antigen
H and Se genes chromosome location
chromosome 19
ABO gene chromosome location
chromosome 9
genes that are not part of the ABO system
H and Se genes
H glycosyltransferase and immunodominant sugar
a-2-L-fucosyltransferase
L-fucose
A glycosyltransferase and immunodominant sugar
a-3-N-acetylgalactosaminyltransferase
N-acetyl-D-galactosamine
B glycosyltransferase and immunodominant sugar
a-3-a-galactosyltransferase
D-galactose
hh is extremely rare, what do you call its phenotype?
Bombay phenotype
Sese phenotype
secretor
sese phenotype
nonsecretor
fluids in which A, B, and H can be detected in secretors
(STUB-M)
saliva, tears, urine, bile, milk, etc
80% of all group A
A1
20% of all group A
A2
A1 or A1B lectin
Dolichus biflorus
B lectin
Bandeiraea simplicifolia
O lectin (H specificity)
Ulex europaeus
reactivity of anti-H antisera (from greatest to least) (6)
O
A2
B
A2B
A1
A1B
weak A subgroups characteristics (4)
-decreased number of A antigen sites/RBC
-varying degrees of agglutination by human anti-A1B
-presence or absence of anti-A1 in the serum
-increased variability in the detectability of H antigen
tests to subdivide A individuals
secretor studies, adsorption-elution tests, and molecular testing
true or false. patients with Bombay phenotype can be transfused with O blood group
false. Bombay can only receive from another Bombay
gene that mutated in Bombay type
FUTI (H gene)
1st solution to resolve ABO discrepancy
repeat testing the same sample using a saline suspension of RBCs
true or false. when a discrepancy is encountered, results must be recorded, but interpretation of the ABO type must be delayed until the discrepancy is resolved.
true
discrepancy that is associated with unexpected reactions in the reverse typing due to weakly reacting or missing antibodies
group I discrepancies
true or false. group I discrepancies are more common
true
causes of group I discrepancies: (3)
newborns/elderly
leukemia/hypogammaglobulinemia
ABO abs diluted by plasma transfusion
resolution of group I discrepancies
patient history - newborns/elderly
enhance weak/missing reaction - hypogammaglobulinemia (incubation, increase antigen, centrifugation)
discrepancy associated with unexpected reactions in the forward typing due to weakly reaction or missing antigens
group II discrepancy
causes of group II discrepancy (3)
subgroups of A or B
Hodgkins disease
acquired B
resolution of group II discrepancy
enhance weak/missing reaction - (incubation, increase antigen, centrifugation)
defined as the presence of two-cell populations
chimerism
artificial chimera causes (4)
blood transfusions
transplanted bone marrows
exchange transfusions
fetal-maternal bleeding
discrepancies caused by protein or plasma abnormalities
group III discrepancies
result of group III discrepancies
rouleaux formation
causes of group III discrepancies
elevated levels of globulin (Waldenstrom macroglobulinemia)
elevated levels of fibrinogen
wharton’s jelly
resolution to remove pseudoaggregation of wharton’s jelly
wash 6-8x with saline
resolution of group III discrepancy
replace serum with saline
discrepancies due to miscellaneous problems
group IV discrepancies
causes of group IV discrepancies:
-cold reactive autoantibodies
-patient has more than 1 ABO type due to RBC transfusion or narrow/stem cell transplant
-unexpected ABO isoagglutinins
-unexpected non-ABO alloantibodies
resolution of group IV discrepancies
incubate > wash with saline 3x > retype
if not successful, add 0.01M DTT to disperse IgM-related agglutination
