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ABO Typing Discrepancies

Jayme Heimonen MT(ASCP)SBBBlood Bank Technical Specialist

Borgess Medical CenterKalamazoo, MI

ASCLS-Michigan 2016

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ABO Typing Discrepancies

• Expected reactions are missing

Anti-A Anti-B Anti-D Co A1 Cells B Cells 4+ 0 4+ 0 0 0

Anti-A Anti-B Anti-D Co A1 Cells B Cells 0 0 4+ 0 0 3+

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ABO Typing Discrepancies

• Unexpected reactions are present.

Anti-A Anti-B Anti-D Co A1 Cells B Cells 4+ 0 4+ 0 2+ 4+

Anti-A Anti-B Anti-D Co A1 Cells B Cells 4+ 2+ 4+ 2+ 0 4+

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ABO Typing Discrepancies

• Reactions are weaker than expected.

Anti-A Anti-B Anti-D Co A1 Cells B Cells 1+ 0 4+ 0 0 4+

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ABO Typing Discrepancies

First Steps;• Always repeat the testing in all tubes or

microtubes, following your SOPs and the manufacturers product insert.

• Repeat using washed cells (at least 3 times).• Observe tube testing reactions microscopically if

possible.• Obtain the patient’s history including age,

transfusion history and diagnosis.

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ABO Typing Discrepancies

Next steps:• Evaluate the reactions in the forward and reverse

typing to determine which type is most convincing.

• Remember: Forward type tests the antigens on the cells. Reverse type test the antibody in the plasma.

• Determine what ABO group to crossmatch for the patient.

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ABO Typing Discrepancies

What can lead to forward type discrepancies?• Transfusions with other ABO types• Weak Subgroups• Mixed cell population (HSCT)• Certain disease states• Rouleaux

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ABO Typing Discrepancies

Example with Transfusions***Expected reaction is missingAnti-A Anti-B Anti-D Co A1 Cells B Cells 4+ 0*** 4+ 0 0 0

AB patient massively transfused with Group: A red blood cells.

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ABO Typing Discrepancies

Group: AB patient massively transfused with Group: A red blood cells.• Phone call to other hospital where transfusions

were administered. Have they typed a pre-transfusion specimen?

• Observe reactions microscopically(tube testing)-may see weak reactions with patient’s cells and anti-B.

• Transfuse with Group: AB, A, B or O cells

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ABO Typing Discrepancies

Weak subgroups***Expected reaction is missingAnti-A Anti-B Anti-D Co A1 Cells B Cells 0*** 0 4+ 0 0 3+Weak subgroup of A such as Am• Adsorption/elution.• Secretor testing.• Transfusion with Group: O red blood cells.

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ABO Typing Discrepancies

Mixed cell population***Expected reaction is weakerAnti-A Anti-B Anti-D Co A1 Cells B Cells 1+*** 0 4+ 0 0 3+

Group: O patient who received a Group: A HSCT in last 30 days.

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ABO Typing Discrepancies

Group: O patient who received a Group: A HSCT in last 30 days.• Call the Blood Bank of the transplant hospital for

their transfusion guidelines.• Transfuse Group: O red blood cells until there is

evidence marrow has engrafted.• Transfuse Group: A plasma product to be compatible

with newly produced red blood cells.• Transfuse irradiated blood products.

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ABO Typing Discrepancies

Disease states such as acute myeloid leukemia and other cancers with chemotherapy.***Expected reaction is weakAnti-A Anti-B Anti-D Co A1 Cells B Cells 0 1+*** 4+ 0 3+ 0• Previous typing history.• Enhance agglutination.• Adsorption/elution.

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ABO Typing Discrepancies

Disease states such as warm autoimmune hemolytic anemia***unexpected reactionAnti-A Anti-B Anti-D Co A1 Cells B Cells 4+ 2+*** 4+ 2+*** 0 4+• Spontaneous agglutination-cells coated with high

concentration of warm autoantibodies.• Perform direct antiglobulin test.• Always give Group: O blood until discrepancy is

resolved.

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ABO Typing Discrepancies

Disease states such as Cold Hemagglutinin diseaseAnti-A Anti-B Anti-D Co A1 Cells B Cells 4+ 3+ 4+ 3+ 0 4+• Incubate type at 37oC.• Wash cells in 37oC saline. • Prewarm reagents and serum/plasma.

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ABO Typing Discrepancies

RouleauxAnti-A Anti-B Anti-D Co A1 Cells B Cells 4+ 2+ 2+ 2+ 2+ 4+Microscopically observe cells as a stacked coin retractile appearance:Anti-A Anti-B Anti-D Co A1 Cells B Cells 4+ R R R R 4+• Saline replacement.

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ABO Typing Discrepancies

What can lead to reverse type discrepancies?• Weak or missing antibodies.• Extra antibodies.• Transfusion.• HSCT recipient.• Rouleaux.

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ABO Typing Discrepancies

Weak or missing antibodies***Expected reaction missingAnti-A Anti-B Anti-D Co A1 Cells B Cells 4+ 0 4+ 0 0 0***Elderly patient with low anti-B titer• Incubate all tubes including autocontrol at room

temperature for 30 min or 4oC.• Increase serum/plasma to cell ratio.• Increase incubation time.• Transfuse with Group: A red blood cells.

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ABO Typing Discrepancies

Weak or missing antibodies***Expected reaction missingAnti-A Anti-B Anti-D Co A1 Cells B Cells 0 4+ 4+ 0 0*** 0Increased antibody concentration where antibody exhibits prozoning.• Perform isohemagglutinin titer.

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ABO Typing DiscrepanciesAtypical antibodies***Unexpected reaction presentAnti-A Anti-B Anti-D Co A1 Cells B Cells 4+ 0 4+ 0 2+*** 4+Weak subgroup of A with anti-A1 present.• Type patient’s cells with A1 lectin.• Test patient’s serum/plasma with cells lacking A1 antigen

(such as A2 cells).• Perform antibody identification for anti-A1.• Transfuse Group: A cells lacking A1 antigen or Group: O cells.

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ABO Typing Discrepancies

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ABO Typing Discrepancies

Atypical antibodies***Unexpected reaction presentAnti-A Anti-B Anti-D Co A1 Cells B Cells 4+ 0 4+ 0 2+*** 4+Patient with alloantibody (anti-M, Anti-N, anti-P1, anti-Lea or anti-Leb).• Perform antibody identification procedures.• Test patient with A1 cell lacking antigen.

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ABO Typing Discrepancies

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ABO Typing Discrepancies

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ABO Typing Discrepancies

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ABO Typing Discrepancies

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ABO Typing Discrepancies

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ABO Typing Discrepancies

Transfusion***Unexpected reactionAnti-A Anti-B Anti-D Co A1 Cells B Cells 4+ 4+ 4+ 0 0 3+***Group AB patient transfused with Group O cryoprecipitate.

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ABO Typing Discrepancies

Hematopoietic stem cell recipient

Anti-A Anti-B Anti-D Co A1 Cells B Cells 0 1+ 4+ 0 0 1+Group: A recipient transplanted with Group: B donor at day 56• Contact the transplant hospital and get their

guidelines for transfusion of packed red cells and plasma products.