Policies and procedures related to testing for weak D phenotypes and administration of Rh immune globulin: results and recommendations related to supplemental questions in the Comprehensive Transfusion Medicine survey of the College of American Pathologists.
BACKGROUND
Advances in RHD genotyping offer an opportunity to update policies and practices for testing weak D phenotypes and administration of Rh immune globulin to postpartum women.


OBJECTIVE
To repeat questions from a 1999 College of American Pathologists proficiency test survey, to evaluate current practices for testing for weak D and administration of Rh immune globulin, and to determine whether there is an opportunity to begin integrating RHD genotyping in laboratory practice.


METHODS
The College of American Pathologists Transfusion Medicine Resource Committee sent questions from the 1999 survey to laboratories that participated in the 2012 proficiency test survey. The results of the 2012 survey were compared with those from 1999. Results from published RHD genotyping studies were analyzed to determine if RHD genotyping could improve current policies and practices for serological Rh typing.


RESULTS
More than 3100 survey participants responded to the 2012 questions. The most significant finding was a decrease in the number of transfusion services performing a serological weak D test on patients as a strategy to manage those with a weak D as Rh negative (from 58.2% to 19.8%, P < .001). Data from RHD genotyping studies indicate that approximately 95% of women with a serological weak D could be managed safely and more logically as Rh positive.


CONCLUSIONS
Selective integration of RHD genotyping policies and practices could improve the accuracy of Rh typing results, reduce unnecessary administration of Rh immune globulin in women with a weak D, and decrease transfusion of Rh-negative red blood cells in most recipients with a serological weak D phenotype.
From the Department of Pathology and Laboratory Medicine, MedStar Georgetown University Hospital, Washington, DC (Dr Sandler); Department of Pathology, Virginia Commonwealth University School of Medicine, Richmond (Dr Roseff); Department of Pathology, Penn State College of Medicine, Hershey, Pennsylvania (Dr Domen); New York Blood Center, New York, New York (Dr Shaz); and Blood Center of Wisconsin and Department of Pathology, Medical College of Wisconsin, Milwaukee (Dr Gottschall).
S Gerald
SG
Sandler
Susan D
SD
Roseff
Ronald E
RE
Domen
Beth
B
Shaz
Jerome L
JL
Gottschall
D001803:Blood Transfusion / Q000706:statistics & numerical data*; D004912:Erythrocytes / Q000276:immunology; D005260:Female; D005838:Genotype; D006306:Health Surveys; D006801:Humans; D007159:Immunologic Tests / Q000379:methods*; D059021:Laboratory Proficiency Testing / Q000592:standards*; D010641:Phenotype; D049590:Postpartum Period / Q000276:immunology; D012204:Rh-Hr Blood-Group System / Q000235:genetics*; D018029:Rho(D) Immune Globulin / Q000627:therapeutic use*; D011795:Surveys and Questionnaires; D064826:Transfusion Medicine
D012204:Rh-Hr Blood-Group System; D018029:Rho(D) Immune Globulin; C026410:Rho(D) antigen