How I manage donors and patients with a weak D phenotypeFlegel, Willy ACurrent Opinion in Hematology: November 2006 - Volume 13 - Issue 6 - p 476–483 doi: 10.1097/01.moh.0000245694.70135.c3 Transfusion medicine Buy Abstract Author InformationAuthors Article MetricsMetrics Purpose of review Since the adoption of molecular blood-group typing, the considerable heterogeneity of the serologic entities weak D and DEL at the molecular level has come to light. I offer an approach to the management of donors and patients expressing D antigen weakly and carrying any of the various molecular types of weak D and DEL. Recent findings More than 50 distinct weak D alleles have been described. An internet-based survey of anti-D immunizations occurring in D-positive transfusion recipients reveals that no allo-anti-D has been observed in patients carrying prevalent weak D types. Allo-immunizations are documented for weak D types 4.2 (also known as DAR), 11 and 15. Anti-D immunizations have been reported in D-negative persons transfused with weak D and DEL red blood cells. Summary Patients carrying any of the prevalent weak D types 1, 2, 3 or 4.1 are not prone to allo-anti-D immunization and may safely be transfused with D-positive red blood cells. Pregnant women with these weak D types need not receive RhIg. We should pay attention to weak D- or DEL-positive blood units that are labelled D-negative. The clinical benefit of removing DEL blood units from our supply of D-negative red blood cell units should be determined. Institute for Clinical Transfusion Medicine and Immunogenetics, Ulm, and Institute for Transfusion Medicine, University Hospital Ulm, Ulm, Germany Correspondence to Professor Dr med Willy A. Flegel, Institut für Transfusionsmedizin, Universitätsklinikum Ulm, Helmholtzstraße 10, 89081 Ulm, Germany Tel: +49 731 150 600; fax: +49 731 150 602; e-mail: firstname.lastname@example.org Work for this review was supported by DRK-Blutspendedienst Baden-Württemberg, Hessen, Mannheim; and Deutsche Gesellschaft für Transfusionsmedizin und Immunhämatologie (grant DGTI/fle/03-01). © 2006 Lippincott Williams & Wilkins, Inc.