Post on 10-May-2018
ABO Typing Discrepancies
Jayme Heimonen MT(ASCP)SBB Blood Bank Technical Specialist
Borgess Medical Center Kalamazoo, MI
ASCLS-Michigan 2016
1
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+
2
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+
3
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+
4
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.
5
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.
6
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
7
ABO Typing Discrepancies
Example with Transfusions
***Expected reaction is missing
Anti-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.
8
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
9
ABO Typing Discrepancies
Weak subgroups
***Expected reaction is missing
Anti-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.
10
ABO Typing Discrepancies
Mixed cell population
***Expected reaction is weaker
Anti-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.
11
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.
12
ABO Typing Discrepancies
Disease states such as acute myeloid leukemia and other cancers with chemotherapy.
***Expected reaction is weak
Anti-A Anti-B Anti-D Co A1 Cells B Cells
0 1+*** 4+ 0 3+ 0
• Previous typing history.
• Enhance agglutination.
• Adsorption/elution.
13
ABO Typing Discrepancies
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.
14
ABO Typing Discrepancies
Disease states such as Cold Hemagglutinin disease
Anti-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.
15
ABO Typing Discrepancies
Rouleaux
Anti-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.
16
ABO Typing Discrepancies
What can lead to reverse type discrepancies?
• Weak or missing antibodies.
• Extra antibodies.
• Transfusion.
• Bone Marrow recipient.
• Rouleaux.
17
ABO Typing Discrepancies
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.
18
ABO Typing Discrepancies
Weak or missing antibodies
***Expected reaction missing
Anti-A Anti-B Anti-D Co A1 Cells B Cells
0 4+ 4+ 0 0*** 0
Increased antibody concentration where antibody exhibits prozoning.
• Perform isohemagglutinin titer.
19
ABO Typing Discrepancies
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.
20
ABO Typing Discrepancies
21
ABO Typing Discrepancies
Atypical antibodies
***Unexpected reaction present
Anti-A Anti-B Anti-D Co A1 Cells B Cells
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.
22
ABO Typing Discrepancies
23
ABO Typing Discrepancies
24
ABO Typing Discrepancies
25
ABO Typing Discrepancies
26
ABO Typing Discrepancies
27
ABO Typing Discrepancies
Transfusion
***Unexpected reaction
Anti-A Anti-B Anti-D Co A1 Cells B Cells
4+ 4+ 4+ 0 0 3+***
Group AB patient transfused with Group O cryoprecipitate.
28
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.
29