ADDENDA Sept. 20, 2005

10. A transfusion medicine physician in Buenos-Aires, Argentina reports that his hospital tests for "dangerous donors" before using group 0 plasma containing products for non-group O recipients. They transfuse, if possible, blood from the same ABO group, but if ABO identical products are not available, they select a "non dangerous" component. They have chosen a final dilution cut-off of 1:64 for anti-A and anti-B, according to the International Forum from 16 experts (Transfusion of apheresis platelets and ABO groups. Vox Sanguinis 2005; 88: 207-221). Their policy applies for all components, but especially to apheresis platelets. According to Lozano and Cid (The Clinical Implications of Platelet Transfusion Associated With ABO or Rh (D) Incompatibility. Transfusion Medicine Reviews 2003; 17: 57-68) there have been 15 reports of hemolysis after a platelet transfusion (12 were from apheresis platelets and 3 from random donor pool). The British Guidelines for the Use of Platelet Transfusions (Br J Haematol 2003; 122: 10-23) establishes: "Group 0 platelets should only be used for group A, B and AB patients if they have been tested and labeled as negative for high-titer anti-A or anti-B (grade B recommendation, level III evidence)".

ADDENDA Sept. 20, 2005

11. A Quality Manager at the Blood and Tissue Bank of Cantabria Santander, Spain reports that they test for anti-A titer on all group O platelet donations. According to their protocol, titers greater than 64 are recorded in a database and printed on the product label. They use an immediate spin test in tube and titration by the classical saline dilultion technique. The titer does not affect the donor's management or status, since whole blood or apheresis platelets can be collected from individuals whose anti-A titers are greater than 64. However, the product labeling allows the hospital pathologist in charge of transfusion to decide on the use of such products. Usually plasma by apheresis from whole blood donations with high titer anti-A are not transfused to group A patients except in critical emergencies. As far as he knows, this has never happened. Platelets donated by apheresis with high titer anti-A are transfused to group A patients only if a dire emergency arises. Red cells collected from donors with high titer anti-A are used without concern for group A patients, since their plasma content has been reduced with processing. However, group O RBCs are not transfused to group A patients unless group A RBCs are unavailable.

ADDENDA Oct. 3, 2005

12. A hospital Transfusion Safety Technologist in Montreal, Canada reports that in order to maintain a continuous stock of platelets for trauma patients, her hospital network orders platelets from their blood supplier up to twice daily with the goal of maintaining a stock of platelets sufficient for 7 platelet transfusions/day at site A and 4/day at site B. She reports that their platelet inventory is comprised of mainly group A platelets, fewer group O platelets, and they try to keep at least 1 group B or 1 group AB platelet on hand. In addition they strive for at least half of their inventory to be 'CMV-negative' and irradiated. They try to stock apheresis platelets as a priority, but often must receive 'random donor' platelets, due to product availability. They try to avoid issuing platelets for transfusions that contain ABO antibodies that are incompatible with the recipient's red cells, but they will issue plasma incompatible platelets if the products in their inventory are at risk of expiration. In order to "feel safe doing this", they perform titer testing using a 1/50 dilution of the product by an immediate spin test before releasing platelets that contain ABO incompatible plasma, and limit (when possible) the use of platelets that have a titer > 50 to group O patients. However, if they do not have plasma compatible platelets or platelets with low titer incompatible ABO antibodies, they notify the patient's doctor and note in the patient's record so as to avoid the same patient getting a second dose of platelets containing incompatible ABO antibodies. They implemented this strategy because several years ago they had a hemolytic adverse event when a group A patient received a second transfusion of group O platelets. Since implementing the above strategy, they are unaware of any subsequent hemolytic reaction due to the transfusion of plasma incompatible platelets.

ADDENDA Nov. 1, 2005

13. A South African physician reports that in ADDENDA #11 from September 20, 2005, a Quality Manager at the Blood and Tissue Bank of Cantabria Santander, Spain implied that transfusing a unit of RBC from a donor with high titer Anti-A should not be of concern because the plasma content of such an RBC unit would be reduced during routine processing. The South African physician wants to know if such a lack of concern would apply for a transfusion of a group O RBC unit into a two week old Group A Rh positive premature neonate whose parents have opted for directed donations rather than using "banked blood". In this case, the baby's father is Group O Rh positive and the mother is Group A Rh positive. The mother is unable to donate according to local guidelines, having delivered the baby just two weeks earlier by Caesarean section. The father's red cells are crossmatch compatible with the baby's serum using a low ionic reagent (LIR) technique which is similar to LISS; the crossmatch reportedly included both a LIR immediate spin test and a LIR indirect antiglobulin test. The mother's serum was tested against her baby's red cells and against the father's red cells; both tests failed to show the presence of maternal alloantibodies. The father's plasma was tested for anti-A antibody titer, which = 128 using a saline indirect antiglobulin test. The inquiring colleague wonders if a directed donor unit of RBCs collected from the father can be safely transfused to the baby, or if it is necessary to wash the paternal RBC unit before transfusing it? If the paternal unit is used as a directed donation, it would be irradiated, regardless if it is washed. The local policy for directed donations from blood relatives requires that such units be irradiated to prevent GVHD.

ADDENDA Nov. 2, 2005

14. In response to ADDENUM #13 of November 1, 2005 in which a South African physician asks if one should be concerned with the transfusion of group O packed red cells into a two week old Group A Rh positive premature neonate whose parents have opted for directed donations rather than using "banked blood", a transfusion medicine physician in New York comments that in his practice unwashed Group O packed red cells are routinely used for neonates who need red cell transfusions. In fact, he believes that the use of unwashed red cells for neonates to be the customary practice in the US, in that many blood centers routinely provide Pedipaks of group O red cells for neonatal transfusion therapy.

15. Also in response to ADDENDUM #13, a transfusion medicine physician in Central California is of the opinion that the most important consideration regarding the directed donation of RBCs from a group O father to his group A child is that the RBC unit be irradiated. The California physician hopes that the baby's father is truthful in his responses to the donor eligibility questions, since he believes that the mother is potentially a better donor for a variety of reasons, even if she does not qualify by local guidelines because of her recent C-section. Finally, the California physician comments that in his experience an anti-A titer of 128 in the plasma of a donor RBC unit is borderline in significance, but to minimize any potential problems arising from transfusion of anti-A, he would process the red cells in an additive solution or "wash" them one time. This could be done just before transfusion and right after irradiation to minimize any problems from potassium leakage induced by the irradiation dose.

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