A transfusion medicine physician in Maryland reports that her laboratory recently received a lot of A1 and B reagent red blood cells that were M-positive, causing increased workload due to anti-M in some patients causing forward/reverse ABO group discrepancies. She also reports that the reagent red cell manufacturer advised her laboratory that they did not believe there was a problem with providing A1 and B reagent red blood cells that express M-antigen, although the Maryland physician thinks that her laboratory had previously been provided with A1 and B reagent red blood cells that were negative for the antigens of common cold antibodies. She asks "Is anyone aware of reagent red cell manufacturers that provide A1 and B reagent red cells that are negative for M and Lewis antigens?"

The following comments have been received.

ADDENDA June 28, 2005

1. A Quality Manager of a Blood Bank in a Pennsylvania hospital reports that the package insert for reagent A1 and B cells and labels on the vials state that the reagents are prepared from red cell pools from different donors. The product inserts also states that the cells contain blood group antigens other than A and B, and that it is possible for reactions due to non-ABO antibodies to react in the saline phase of testing. Consequently, it is likely that the Maryland colleague's laboratory (see question above) has probably been performing ABO reverse typing with pooled cells, and that some of the reagent lots have been positive for M and Lewis antigens. In the reference laboratory where the Pennsylvania blood banker has worked, when a potent room temperature antibody created problems with reverse ABO typing, they would screen group A and group B donor RBC units for the offending antigen, and then repeat the reverse typing with the antigen negative units.

ADDENDA July 4, 2005

2. Sheryl A. Kochman, Chief, Devices Review Branch, CBER/OBRR/DBA (attribution used with permission) comments that facilities that find themselves frequently dealing with problems with ABO grouping due to the presence of "cold reactive" antibodies should consider using a Reverse Grouping Cell set that contains a group O cell, which serves as a control for cold agglutinins, antibodies to diluent components, etc. Note; however; that while the O cells will also be from a pool of donors, there is a possibility that they will not include cells from M and/or Lewis positive donors.

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Ira A. Shulman, MD
CBBS e-Network Forum Editor & Moderator