Policies and procedures related to weak D phenotype testing and Rh immune globulin administration: Results from supplementary questions to the comprehensive transfusion medicine survey of the college of american pathologists

Objective. To determine and evaluate policies and procedures related to weak D phenotype testing and terminology and the administration of Rh immune globulin in selected clinical situations. Design, Setting, and Participants. Institutions participating in the College of American Pathologists 1999 J-A Comprehensive Transfusion Medicine Survey program were asked to respond to a series of supplementary questions related to weak D phenotype testing and Rh immune globulin administration. More than 3500 institutions and transfusion services participated. Results. Most supplementary questions elicited more than 3000 responses. Despite no clinical or regulatory mandate, 58.2% of transfusion services routinely perform an antiglobulin test for the weak D phenotype in patients who test negative with anti-D reagents. Significant differences were found concerning the transfusion of blood components to patients with the weak D phenotype and the administration of Rh immune globulin to these individuals. At least one patient with the weak D phenotype with anti-D alloantibody formation was observed during a 12-month period by 31.8% of transfusion services. Conclusions. Significant variability concerning policies and procedures related to weak D typing and terminology was found in this survey. Transfusion of blood components to patients with the weak D phenotype and the administration of Rh immune globulin also demonstrated variations. Anti-D alloantibody formation by patients with the weak D phenotype may not be as rare as previously thought. Additional study related to the clinical significance of these results is warranted.