A blood banker from a University Hospital in the Midwest wants to know the practice of transfusing out of type platelets, for instance giving a group O Plateletspheresis unit to a group B patient. At the Midwesterner's institution they transfuse approximately 20% of their platelets as plasma incompatible Plateletpheresis and they are wondering about the practice in the rest of the country. In addition, the inquiring blood banker would also like to know how many hemolytic or adverse reactions have been noted due to these transfusions, because acute intravascular hemolysis secondary to out-of-group platelet transfusion has been reported by others, including Larsson LG, Welsh VJ and Ladd VJ in Transfusion Aug., 2000. For example, the aforementioned authors reported on a 44-year-old woman, blood group A, who was recently diagnosed with acute myeloid leukemia and was receiving chemotherapy. After the transfusion of apheresis platelets from a group O donor, back pain, hemoglobinuria, and hemoglobinemia developed, and her Hb dropped by 2.3 g per dL, despite the transfusion of 2 units of RBCs. Investigation revealed acute intravascular hemolysis with a positive DAT due to anti-A1 on her RBCs. The donor's titer of anti-A1 was greater than 16,000. Review of published cases raises the possibility that hemolytic reactions to out-of-group platelets may be more frequent since the use of apheresis platelets has increased. Other links of interest include: 

• Reducing supernatant plasma of pooled platelets before administration to ABO-incompatible adult recipients
• Washed and volume-reduced Plateletpheresis units

The following replies were submitted in response to the above.

1. A blood banker from Virginia reported on his hospital's policy to only transfuse plasma-incompatible plateletpheresis products that have an anti-A and/or anti-B titer less than 200. (See technique in May 11 Addendum below.) Using their approach, he reports that they have not had any cases of intravascular hemolysis from plateletspheresis products while following this protocol. 

2. A blood bank physician from New York reported that at his hospital the consequences ABO out-of-group transfusions may be much more serious immunologically and clinically than mild hemolytic transfusion reactions. The consequences of repeated ABO-mismatched transfusions clearly include reduced platelet count increments and an increased incidence of platelet transfusion refractoriness (data from randomized clinical trials). The responding blood banker has summarized this finding and other possible changes in clinical outcomes in an editorial in Transfusion (39: 1155-1159, 1999) and in a recent paper in Transfusion (41: 790-793, 2001. Their own practice is to almost never give ABO antigen or antibody incompatible platelets to patients receiving repeated platelet transfusions and they are now trying hard to avoid giving them to anyone. That's obviously a lot easier in a large university hospital using 15-20 transfusions a day than in smaller hospitals with inventory issues.

3. A medical director of a large transfusion service on the East coast who wishes to remain nameless on this item has the following comment:

"The problem of out-of-group platelets represents another example of the disadvantage of single donor apheresis platelets over pooled whole blood platelets. Recipients of single donor platelets from donors with high-titre isohemagglutins receive a large volume of plasma exclusively from one donor. It is reasonable to assume that pooling whole-blood-derived platelets decreases the risk from a variety of adverse consequences including out-of-group plasma, allergic reactions to donor factors, TRALI, etc. It is time to reconsider the prevailing opinion that apheresis platelets are a safer product." (Editor's note: e-Networkers may be interested in the following link - Usage of Pooled Platelets vs. Pheresis Platelets) 

ADDENDA May 11, 2002

4. In reference to the titer technique used by the Virginia transfusion service (in reply #1 above): "It is a straight immediate spin read at a 1 to 200 dilution. There is no antihuman globulin enhancement, and the test is interpreted as positive or negative. If the test result is positive, those platelets cannot be transfused to a patient whose red cells will react with the transfused ABO antibody." The Virginian reports that this approach has worked very well for them, with no reported hemolysis ever with this procedure in place.

5. A retired blood bank physician in Northern California offers this question and suggestion: "Aside from the transfusion service in Virginia and those in the U.K., I wonder how many others screen the plasma of their group O platelet donors for high-titer anti-A/B? Identifying such products seems like an easy and inexpensive approach to averting potentially troublesome hemolytic complications when out-of-type platelets need to be transfused. Knowing that the plasma of these platelets did not have high-titer anti-A/B might also comfort those physicians who feel uneasy about accepting "incompatible" platelets when the plasma-compatible ones are unavailable. Has the AABB Standards Committee considered this?"

ADDENDUM May 13, 2002

6. The blood banker from Virginia (who already mentioned that they restrict ABO plasma- incompatible platelet transfusions to those units with low titer anti-A and anti-B) has provided their procedures (MS Word files) for platelet donor ABO antibody titers and for selection of platelet products. It is their understanding that blood centers could easily perform a direct agglutination test with diluted donor plasma/serum with an automated blood typing instrument, should this become an accepted practice. [Note: These two procedures have been reproduced almost exactly as they were provided, except for very minor edits that were necessary due to some minor font issues (in other words, they seem to have used a PC to write their procedures and I used a MAC to read them).]

ADDENDUM May 14, 2002

7. A blood banker from Leeds, UK, thought that the e-network forum might be interested in a paper recently published by the National Blood Service Clinical Policies Group (PDF) on the subject of hemolysis thought to be due to high-titre anti-A/B, and what measures are being taken to prevent this complication.

ADDENDA Sept. 2, 2005

8. A transfusion medicine physician at a blood center in the Midwest wants to know what is common practice at other blood centers and hospital blood banks when managing group O blood donors who have high titer anti-A and anti-B. In particular, their center has a donor who was implicated in a severe hemolytic transfusion reaction when a single apheresis platelet unit was transfused to a group A patient. The donor's anti-A titer testing was determined by a tube technique by direct agglutination at room temperature (titer = 256) and by indirect antiglobulin testing with anti-IgG anti-human globulin (titer = 16,000). This donor has donated more than 200 times, with over 100 donations of apheresis platelets. No other hemolytic reactions were reported to be associated with previous transfusions from this donor's blood products. This colleague wants to know if other blood centers would defer such a donor temporarily, and test the titer again before reinstating him, or would they defer him indefinitely, or are there other blood centers who titer group O apheresis platelets at each donation. Are packed red cells acceptable for ABO non-identical recipients because of the minimal amount of plasma present? In this particular case the donor will be allowed to only donate platelets, and the collected platelet units will be tagged indicating that they are for transfusion of ABO identical recipients only.

ADDENDA Sept. 8, 2005

9. A transfusion medicine physician in Sacramento with many years experience in a donor center environment is of the opinion that the donor described in the ADDENDA of Sept. 2, 2005 above should be allowed to donate packed cells, preferably into an additive solution to minimize the amount of plasma left on the packed cells. He would keep the donor as a platelet donor, too but just use the platelets for Group O recipients. If the donor were an HLA match for a Group A recipient, he would recommend that the platelets be volume reduced and/or resuspended in a suitable solution.

Please submit comments to the e-Network Forum.

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