ABO Discrepancy Assignment Spring 2021
1. Patient is a 24 year old female with no prior transfusions needs a crossmatch of 2 units
RBCs.
Automated Typing
Reagent Anti-A Anti-B Anti-D A1 Cells B Cells Interpretation
Results 4+ 0 4+ 1+ 3+ A+
Repeat Tube Typing
Reagent Anti-A Anti-B Anti-D D A1 B Cells Interpretation
control Cells
Results 4+ 0 4+ NT 1+ 4+ A+
Saline Replacement Tube Typing
Reagent Anti-A Anti-B Anti-D D A1 B Cells Interpretation
control Cells
Results 4+ 0 4+ NT 1+ 4+ A+
What blood type does this patient have? What is a possible discrepancy the patient
might have? Why? What would you do next to confirm it and what results do you expect
to see?
This patient has a blood type of A+. The patient has a possible group 1 discrepancy as
the front type shows a 4+ with Anti-A but the back type shows a 1+ reaction with A1
cells and 4+ with B cells. The patient possibly belongs to a subgroup of A such as A2 with
anti-A1. To confirm this, the patient cells should be reacted with anti-A1 lectin which is
expected to have a negative reaction.
2. Patient is a 5 month old female with a history of transfusions needs a crossmatch of 1
units RBCs.
Tube Typing
Reagent Anti-A Anti-B Anti-D D A1 B Cells Interpretation
control Cells
Results 0 0 4+ NT 0 0 O+
Repeat Tube Typing
Reagent Anti-A Anti-B Anti-D D A1 B Cells Interpretation
control Cells
Results 0+ 0 4+ NT 0 0 O+
What blood type does this patient have? What is the possible discrepancy the patient
might have? Why? What would you do next to confirm it and what results do you expect
to see?
This patient has a blood type of O+. The patient has a possible group 1 discrepancy
where the reverse grouping lacks a strong reaction for A1 and B cells compared to the
reactions indicated on the front type. This is due to the patient being 5 months old and
how newborns ages 3 to 6 months cannot produce ABO antibodies. A direct antiglobulin
test can be used to confirm the absence of newborn antibodies and is expected to have
a negative reaction.
Professor comment:
Because the reverse type was tested on the baby that means it is appropriate for the
age and that it is our responsibility to attempt to resolve the issue. Antibodies can
develop starting 3-6 months but will be weak so we need to incubate RT and 4C.
-3 pts
3. Patient is a 6 year old male with leukemia and a history previous transfusions needs a
crossmatch of 2 units RBCs.
Typing from 1 year ago
Reagent Anti-A Anti-B Anti-D A1 Cells B Cells Interpretation
Results 4+ 0 4+ 0 3+ A+
Present Automated Typing
Reagent Anti-A Anti-B Anti-D A1 Cells B Cells Interpretation
Results 1+ 0 4+ 3+ 4+ O+
Repeat Tube Typing
Reagent Anti-A Anti-B Anti-D D A1 B Cells Interpretation
control Cells
Results 1+ 0 4+ NT 3+ 4+ O+
What blood type does this patient have? What is a possible discrepancy the patient
might have? Why? What would you do next to confirm it and what results do you
expect?
This patient has a blood type of A+. Blood typing the patient one year ago indicates a
blood type of A+. Present typing indicates a blood type of O+ from the back type but
with a weak reaction of 1+ for Anti-A on the front type. This is possibly due to a group 2
discrepancy due to the patient having leukemia. Leukemia most likely has caused the
weakened A antigens on the present forward type. This combined with the patient’s
history of transfusions of possible O blood may have contributed to the reason why
there is a strong reaction in the back type to have indicated blood group O. This
discrepancy can be resolved by incubating the mixture at room temperature for 30
minutes in order to increase the association of the antibody with the weakened A
antigen to get a stronger positive reaction. However, if the reaction is still negative, then
the mixture should be incubated at 4°C from 15 to 30 minutes. Getting the transfusion
history should also help in confirming whether the patient received type O blood.
Professor comment:
3. The only thing you would need to elaborate on is not only that the patient has
leukemia, but that they are receiving this specific treatment and that you would need to
perform an Elution and adsorption to see if there is a positive test for A cells. You should
also mention that once the treatment is done that the patient would revert back to the
original blood type.
-2pts
4. Patient is a 60 year old male with colon cancer and has no prior transfusions needs a
type and screen.
Automated Typing
Reagent Anti-A Anti-B Anti-D A1 Cells B Cells Interpretation
Results 4+ 1+ 4+ 0 3+ A+
Repeat Tube Typing
Reagent Anti-A Anti-B Anti-D D A1 B Cells Interpretation
control Cells
Results 4+ 1+ 4+ NT 0 4+ A+
What blood type does this patient have? What is a possible discrepancy the patient
might have? Why? What would you do next to confirm it and what results do you expect
to see?
This patient has a blood type of A+. The patient possibly has a group 2 discrepancy
where the forward type indicates AB with a weak 1+ anti-B antisera reaction but the
back type shows a strong reaction for B cells that would indicate type A. The unexpected
weak 1+ reaction of the forward type for anti-B antisera most likely is from the
“acquired B” phenomenon which occurs in patients with colon cancer. The acquired B
antigen comes from bacterial enzyme activity modifying blood group A sugar called N-
acetyl-D-galactosamine into D-galactosamine. D galactosamine is similar enough to the
group B sugar of D-galactose that it can react with anti-B antisera. The likeliness of this
being the cause can be further confirmed by checking to see if the patient has a
bacterial infection. The pseudo-B antigen should disappear after the patient recovers.
The anti-B reagent can be acidified and reacted with the acquired B antigen. The
absence of agglutination confirms the presence of acquired B antigen.
5. Patient is a 55 year old male with no prior transfusions needs a type and screen.
Automated Typing
Reagent Anti-A Anti-B Anti-D A1 Cells B Cells Interpretation
Results 4+ 4+ 4+ 1+ 1+ AB+
Repeat Tube Typing
Reagent Anti-A Anti-B Anti-D D A1 B Cells Interpretation
control Cells
Results 4+ 3+ 4+ 0 1+ 1+ AB+
What blood type does this patient have? What is a possible discrepancy the patient
might have? Why? What would you do next to confirm it and what results do you expect
to see?
The patient has a blood type of AB+. The front type indicates a blood type of AB
whereas the back type indicates a blood type of O. This is indicative of a group 4
discrepancy where a likely cause can be the unexpected presence of alloantibodies in
the patient’s serum that agglutinate with antigens other than A1 and B on the reagent
blood cells. In this scenario, an antibody identification panel should be conducted using
the patient’s serum to identify the unexpected alloantibodies.
