A transfusion medicine physician in Ohio wonders if platelet apheresis donors should be routinely screened (tested) for evidence of platelet dysfunction, given the plethora of medications, foods, and medical conditions that might effect platelet function. She believe that the use of a platelet function test (such as the Thromboelastograph (TEG®) or PFA-100®) would be more objective than trying to figure out what substances are being consumed or what medical conditions exist. She suggests that such an approach might result in the collection of more uniformly functional platelet products. Are any institutions using testing protocols to assess the functionality of donor platelet products?

The following comments have been received.

ADDENDA Apr. 25, 2005

1. In a report by Harrison and colleagues from the Oxford Hemophilia Center and Thrombosis Unit, Churchill Hospital, Headington, Oxford, UK the authors conclude that platelet dysfunction as detected by the PFA-100® is surprisingly common within a voluntary platelet donor population. The majority of defects detected by the PFA-100® appeared transient in nature and indicative of surreptitious intake of cyclooxygenase inhibitors (e.g., aspirin). The authors conclude that the identification of defective platelet function within donors would provide a simple means to eradicate defective platelets from being used clinically.

ADDENDA Apr. 26, 2005

2. The Medical Director of a Blood Bank and Transfusion Service in Michigan reports that while there may be 'abnormalities' detected by PFA-100® testing, the study referenced in the ADDENDUM of April 25, 2005 (ADDENDUM #1 above) from the Oxford Hemophilia Center and Thrombosis Unit, Churchill Hospital, Headington, Oxford, UK did not assess hemostatic function in vivo. The Michigan physician is not aware of any data that such platelets have less clinical effiicacy. He cautions that given our current state of frequent shortages of apheresis platelets (at least in Michigan) he would be very hesitant to recommend such a screening test until we have data from a clinical trial.

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