The ISBT Working Party (WP) Red Cell Immunogenetics and Blood Group Terminology maintains the official registry for all recognized blood group systems, and establishes standardized naming conventions for blood group systems, antigens and alleles used in transfusion medicine and related fields.
Since November 2025, all blood group allele data has been migrated to our new database system!
Our registry currently includes 48 distinct blood group systems encompassing 371 red cell antigens and 2,017 alleles (as of October 2025). These systems are controlled by 56 different genes. An additional 27 antigens that haven't yet been assigned to specific systems are organized into specialized categories: Collections (200 series), low-prevalence antigens (700 Series), and high-prevalenceantigens (901 Series).
Visit the database at the link above to find comprehensive details about each classification system.
Current Leadership
Margaret A. Keller
Dr. Keller is the Executive of National Laboratories at the American Red Cross, overseeing the National Molecular Laboratory, National Reference Laboratory for Specialized Testing, and the National Neutrophil. She is senior director of the American Rare Donor Program (ARDP). Margaret received her PhD in molecular genetics from the University of Pennsylvania. She is ARDP liaison to the Molecular Testing Standards Unit of the AABB and the secretary of the ISBT Working Party on Red Cell Immunogenetics and Blood Group Terminology and a member of the ISBT Working Party on Rare Donors. She is adjunct Associate Professor at Thomas Jefferson University, is editor-in-chief of the journal Immunohematology and is on the board of South Central Association of Blood Banks.
