ABO System Flashcards
Forward Typing detects
antigens
Reverse Typing detects
antibodies
Test sample for forward typing
RBCs
Test sample for reverse typing
serum or plasma
Reagents for forward typing
anti-A (blue) and anti-B (yellow)
Reagents for reverse typing
A1 and B cells
What is the principle for forward typing?
using known antibodies to detect unknown antigens
What is the principle for reverse typing?
using known antigens to detect unknown antibodies
The H and Se gene are located on which chromosome?
Chromosome 19
Which chromosome are the ABO genes located?
Chromosome 9
What gene needs to be expressed in order for the H gene to be expressed?
Z gene
Which antigen needs to be expressed in order for A and B antigens to be expressed?
H antigen
What happens when an individual doesn’t inherit the H antigen?
There will be no antigen expression due to the lack of the H antigen upon which other antigens build on
An individual who types as A will express which antigens?
H and A antigens
An individual who types as B will express which antigens?
H and B antigens
An individual who types as AB will express which antigens?
H, A, and B antigens
An individual who types as O will express which antigens?
Only H
Bombay phenotype will type as what?
O type
When an individual is homozygous recessive for H, what blood type are they?
Bombay
What is the extract from Dolichos biflorus seeds used to make?
anti-A1 lectin
A1 and A2 cells can be via…
anti-A1 lectin (only binds A1 cells)
What is the extract from Ulex europaeus used to make?
anti-H lectin
Order of ABO antigen reactivity with anti-H lectin
O > A2 > B > A2B > A1 > A1B
Reactivity with anti-H lectin depends on…
accessibility to fucose
In cases where Bombay type may be suspected, what reagent should be used?
anti-H lectin
Type 1 paragloboside originate where and have what linkage of galactose to GALNAC?
Originates in secretions
Beta-1,3 linkage
Type 2 paraglobosides originate where and have what linkage of galactose to GALNAC?
Originate on RBS precursors
Beta- 1,4 linkage
Which paragloboside do RBC antigens build upon?
Type 2
Glycolipid coming off of the RBC surface upon which antigens build
Type 2 paragloboside
What is the order of carbohydrates that compose paraglobosides in order from cell surface out?
Glucose-Galactose-GALNAC-Galactose
Which carbohydrate is added to the precursor substance to make the H antigen?
Fucose
Which enzyme and sugar donor are responsible for the transfer of fucose onto the paragloboside?
Enzyme: a-L-fucosyltransferase
Sugar Donor: guanine-diphosphate-L-fucose
Which carbohydrate is added to the H antigen to make the A antigen?
N-acetylgalactosamine (GALNAC)
Which enzyme and sugar donor are responsible for the transfer of GALNAC to the H antigen?
enzyme: a-3-N-acetyl-D-galactosamine transferase
donor: Uridine-diphosphate-N-acetyl-D-galactose
Which carbohydrate is added to the H antigen to make the B antigen?
D-galactose
Which enzyme and sugar donor are responsible for the transfer of D-galactose to the H antigen?
enzyme: a-3-D-galactosyl transferase
donor: uridine-diphosphate-galactose
How many H structures are there?
4
Which H structures are capable of producing A1?
H1, 2, 3, and 4
Which H structures are capable of producing A2?
H1 and 2
Which subgroup of A cells has more H antigen on RBCs?
A2
Which A cells express less A antigen on RBCs?
A2
Approximately, what percentage of the population has secretor cells?
78%
What does the Se gene control?
The presence of ABH antigens in body fluids
Secretor status is controlled via a dominant, recessive, or co-dominant allele?
Dominant
What is the 1st, 2nd, and 3rd choice of donor blood for a patient with Type O?
1st - O
2nd - none
3rd - none
What is the 1st, 2nd, and 3rd choice of donor blood for a patient with Type A?
1st - A
2nd - O
3rd - none
What is the 1st, 2nd, and 3rd choice of donor blood for a patient with Type B?
1st - B
2nd - O
3rd - none
What is the 1st, 2nd, and 3rd choice of donor blood for a patient with Type AB?
1st - AB
2nd - A or B
3rd - O
What is the 1st, 2nd, and 3rd choice of donor blood for a patient with Type A2 with anti-A1?
1st - A2
2nd - O
3rd - none
What is the 1st, 2nd, and 3rd choice of donor blood for a patient with Type A2B with anti-A1?
1st - A2B
2nd - A2 or B
3rd - O
What is the 1st, 2nd, and 3rd choice of donor blood for a patient with Type Oh?
1st - Oh
2nd - none
3rd - none
