Phenotype Matching of Donor Red Blood Cell Units for Nonalloimmunized Sickle Cell Disease Patients: A Survey of 1182 North American Laboratories

Archives of Pathology & Laboratory Medicine, Feb 2005 by Osby, Melanie, Shulman, Ira A

Context.-The transfusion of donor red blood cell units (RBCs) that lack certain red cell antigens (such as C, E, and K) when the corresponding antigens are absent from the recipient's red cells has been shown to reduce the risk of red cell alloimmunization in sickle cell disease patients. However, data are limited regarding the extent to which transfusion services routinely perform red cell antigen phenotype testing of nonalloimmunized sickle cell disease patients, and then use that information to select donor RBCs lacking 1 or more of the red cell antigens that the patient's red cells do not express.

Objective.-To determine the extent to which transfusion services routinely perform red cell antigen phenotype testing of nonalloimmunized sickle cell disease patients, and then use that information to select donor RBCs lacking 1 or more of the red cell antigens that the patient's red cells do not express.

Design.-An educational subsection of a College of American Pathologists Proficiency Testing Survey (J-C 2003) assessed transfusion service practices regarding performance of red cell antigen phenotype testing of nonalloimmunized sickle cell disease patients and how transfusion services use this information for the selection of donor RBCs. The data analysis of the survey included 1182 North American laboratories.

Results.-Data from 1182 laboratories were included in the survey analysis, of which the majority (n = 743) reported that they did not routinely perform phenotype testing of sickle cell disease patients for antigens other than ABO and D. The other 439 laboratories reported that they did routinely perform phenotype testing of sickle cell disease patients for antigens in addition to ABO and D. The majority of these 439 laboratories (three fourths; n = 330) reported that they used these patient data for prophylactic matching with donor RBCs when sickle cell disease patients required transfusion. When phenotype-matched donor RBCs were used, the antigens most commonly matched (85% of the time) were C, E, and K.

Conclusions.-The majority of North American hospital transfusion service laboratories do not determine the red cell antigen phenotype of nonalloimmunized sickle cell disease patients beyond ABO and D. Those laboratories that do determine the red cell phenotype of nonalloimmunized sickle cell disease patients beyond ABO and D most commonly match for C, E, and K antigens when phenotype-matched donor RBCs are used.

(Arch Pathol Lab Med. 2005;129:190-193)

Sickle cell disease affects approximately 72 000 people in the United States (approximately 1 in 500 African Americans and 1 in 1000 to 1400 Hispanics).1 During the past 30 years, the management of sickle cell disease has improved significantly, such that today, patients with sickle cell disease are living beyond 50 years of age, rather than dying before the age of 14.2 Transfusion therapy has played a role in allowing sickle cell disease patients to live longer.1 However, associated with red blood cell unit (RBC) transfusion is the risk of red cell antigen alloimmunization, and studies show that 25% or more of chronically transfused sickle cell disease patients may experience alloimmunization to red cell antigens.4 Several reports document that the most common clinically significant alloantibodies to develop in transfused sickle cell disease patients include antibodies to the Rhesus blood group system antigens, such as C and E, and to the Kell blood group system antigens, such as K.5-8

Studies have also shown that the transfusion of ABO- and D-compatible donor RBCs that lack C, E, or K antigens when the corresponding antigen(s) are absent on the recipient's red cells can significantly reduce the rate of alloimmunization in patients with sickle cell disease and can also decrease the occurrence of complications such as hemolytic transfusion reactions.4

This report describes the results of a data subset from a recent College of American Pathologists (CAP) Proficiency Testing Survey (J-C 2003). The data subset came from an educational module that was designed to determine the extent to which hospitals perform phenotype testing of nonalloimmunized sickle cell disease patients and then select donor RBCs that lack 1 or more red cell antigens that the patient's red cells do not express.

MATERIALS AND METHODS

The CAP Proficiency Testing Survey J-C 2003 was distributed to 4251 participants to assess their proficiency in testing the following analytes: ABO, Rhesus (Rh), antibody detection, antibody identification, and crossmatching.

A subset of the survey participants (n = 1360) also subscribed to an educational module through which they were surveyed for their routine practice to provide (or not to provide) phenotype-matched donor RBCs for the transfusion of nonalloimmunized sickle cell disease patients. The survey consisted of a case history, a series of short vignettes that pertained to the case history, and follow-up questions that allowed for the survey of laboratory practices (see "Results"). By the data collection deadline (set as 10 working days after receipt of survey materials), participants had submitted their survey responses. The survey focused on whether or not laboratories routinely performed red cell phenotype testing of nonalloimmunized sickle cell disease patients, and if so, whether they used that information for prophylactic matching of donor RBCs for antigens other than ABO and D. No effort was made to stratify the data according to the category of the transfusion (eg, red cell exchange, response to a life-threatening event). In addition, no questions were directed at the participants to determine how they discover that a particular patient has sickle cell disease.