1. Brigham and Women's Hospital; Boston Massachusetts
2. Center for Statistical Analysis and Research; New England Research Institutes; Watertown Massachusetts
3. Department of Pathology; Division of Transfusion Medicine; University of Pittsburgh; Pittsburgh Pennsylvania
4. University of Iowa College of Medicine; Iowa City Iowa
5. Transfusion Medicine Division; Johns Hopkins Medical Institutions; Baltimore Maryland
6. Puget Sound Blood Center; University of Washington Medical Center; Fred Hutchinson Cancer Research Center; Seattle Washington