A blood banker in the Midwestern USA would like feedback regarding transfusion service protocols regarding combining ABO non-identical platelets in the same pooling bag. She says that in her 35 years of experience as a blood bank medical technologist, she has always avoided mixing ABO non-identical platelets in the same pooling bag to avoid interaction between ABO antibodies and incompatible ABO antigens that are expressed on platelets. Based on the aforementioned belief, the official protocol at her transfusion service has been to NOT combine platelets of different ABO groups in the same bag. However, much to her chagrin she has discovered that some of her own technologists have been pooling ABO non-identical platelets in the same bag, during times of blood shortages. She would like to know what is the practice at other facilities, and upon what scientific foundation (including literature references) is that practice based.

The following responses have been received.

ADDENDA Aug. 23, 2004

1. A colleague with 35 years experience in blood banking reports that he has worked at an institution for all of those 35 years. During that time, they have never had a policy prohibiting pooling of platelet concentrates of different ABO types. He acknowledges being unable to provide a scientific basis or any references in literature upon which they have based their practice of pooled platelets of different ABO types. He does comment that they have never had a 'known' adverse outcome due to the practice.

ADDENDA Aug. 27, 2004

2. A medical technologist in the US heartland reports that he is not aware of data either supporting or opposing their past practice of routinely pooling ABO non-identical platelets. He shared the opinion that a negative consequence to pooling ABO non-identical platelets might be failure to achieve an expected increase in platelet count, consequently causing a patient to receive an additional transfusion that might not otherwise have been needed. In correspondence with the Webmaster he asked: "How much longer would the platelets last if they were given in separate pools to a patient that is not of the same ABO type as some of the platelets?" In response, the Editor asked if he was aware of any changes that occur in vitro to the platelets (in the pooling bag) that might be different from what takes place in vivo, due to differences in ABO antibody concentration, platelet concentration, pH, etc. He concluded by saying that their platelet pooling situation has been resolved, now that they have switched from using whole blood derived platelet pools to using plateletspheresis products.

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