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ABO Typing Discrepancies

Jayme Heimonen MT(ASCP)SBB Blood Bank Technical Specialist

Borgess Medical Center Kalamazoo, MI

ASCLS-Michigan 2016

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• Expected reactions are missing

Anti-A Anti-B Anti-D Co A1 Cells B Cells

4+ 0 4+ 0 0 0


0 0 4+ 0 0 3+

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• Unexpected reactions are present.


4+ 0 4+ 0 2+ 4+


4+ 2+ 4+ 2+ 0 4+

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• Reactions are weaker than expected.


1+ 0 4+ 0 0 4+

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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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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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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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Example with Transfusions

***Expected reaction is missing


4+ 0*** 4+ 0 0 0

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

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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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Weak subgroups

***Expected reaction is missing


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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Mixed cell population

***Expected reaction is weaker


1+*** 0 4+ 0 0 3+

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

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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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Disease states such as acute myeloid leukemia and other cancers with chemotherapy.

***Expected reaction is weak


0 1+*** 4+ 0 3+ 0

• Previous typing history.

• Enhance agglutination.

• Adsorption/elution.

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Disease states such as warm autoimmune hemolytic anemia ***unexpected reaction Anti-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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Disease states such as Cold Hemagglutinin disease


4+ 3+ 4+ 3+ 0 4+

• Incubate type at 37oC.

• Wash cells in 37oC saline.

• Prewarm reagents and serum/plasma.

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Rouleaux


4+ 2+ 2+ 2+ 2+ 4+

Microscopically observe cells as a stacked coin retractile appearance:


4+ R R R R 4+

• Saline replacement.

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What can lead to reverse type discrepancies?

• Weak or missing antibodies.

• Extra antibodies.

• Transfusion.

• Bone Marrow recipient.

• Rouleaux.

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Weak or missing antibodies ***Expected reaction missing Anti-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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Weak or missing antibodies

***Expected reaction missing


0 4+ 4+ 0 0*** 0

Increased antibody concentration where antibody exhibits prozoning.

• Perform isohemagglutinin titer.

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Atypical antibodies ***Unexpected reaction present Anti-A Anti-B Anti-D Co A1 Cells B Cells 4+ 0 4+ 0 2+*** 0 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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Atypical antibodies

***Unexpected reaction present


4+ 0 4+ 0 2+*** 0

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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Transfusion

***Unexpected reaction


4+ 4+ 4+ 0 0 3+***

Group AB patient transfused with Group O cryoprecipitate.

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Hematopoietic stem cell recipient


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.

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