ABO Typing Discrepancies

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1 Jayme Heimonen MT(ASCP)SBB Blood Bank Technical Specialist Borgess Medical Center Kalamazoo, MI ASCLS-Michigan

2 Expected reactions are missing

3 Unexpected reactions are present

4 Reactions are weaker than expected

5 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

6 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

7 What can lead to forward type discrepancies? Transfusions with other ABO types Weak Subgroups Mixed cell population (HSCT) Certain disease states Rouleaux 7

8 Example with Transfusions ***Expected reaction is missing 4+ 0*** AB patient massively transfused with Group: A red blood cells. 8

9 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

10 Weak subgroups ***Expected reaction is missing 0*** Weak subgroup of A such as Am Adsorption/elution. Secretor testing. Transfusion with Group: O red blood cells. 10

11 Mixed cell population ***Expected reaction is weaker 1+*** Group: O patient who received a Group: A HSCT in last 30 days. 11

12 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

13 Disease states such as acute myeloid leukemia and other cancers with chemotherapy. ***Expected reaction is weak 0 1+*** Previous typing history. Enhance agglutination. Adsorption/elution. 13

14 Disease states such as warm autoimmune hemolytic anemia ***unexpected reaction 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

15 Disease states such as Cold Hemagglutinin disease Incubate type at 37 o C. Wash cells in 37 o C saline. Prewarm reagents and serum/plasma. 15

16 Rouleaux Microscopically observe cells as a stacked coin retractile appearance: 4+ R R R R 4+ Saline replacement. 16

17 What can lead to reverse type discrepancies? Weak or missing antibodies. Extra antibodies. Transfusion. Bone Marrow recipient. Rouleaux. 17

18 Weak or missing antibodies ***Expected reaction missing *** Elderly patient with low anti-b titer Incubate all tubes including autocontrol at room temperature for 30 min or 4 o C. Increase serum/plasma to cell ratio. Increase incubation time. Transfuse with Group: A red blood cells. 18

19 Weak or missing antibodies ***Expected reaction missing *** 0 Increased antibody concentration where antibody exhibits prozoning. Perform isohemagglutinin titer. 19

20 Atypical antibodies ***Unexpected reaction present *** 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

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22 Atypical antibodies ***Unexpected reaction present *** 0 Patient with alloantibody (anti-m, Anti-N, anti- P1, anti-le a or anti-le b ). Perform antibody identification procedures. Test patient with A1 cell lacking antigen. 22

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28 Transfusion ***Unexpected reaction *** Group AB patient transfused with Group O cryoprecipitate. 28

29 Hematopoietic stem cell recipient 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