The significance of a positive DAT in thalassemia patients

New York Blood Center/New York Presbyterian Hospital, Columbia University Medical Center, Department of Professional Education, New York, NY, USA.
Immunohematology / American Red Cross 09/2010; 26(3):87-91.
Source: PubMed


The DAT is performed for the detection of antibody or complement on the surface of RBCs. Our institution previously performed DATs on all chronically transfused thalassemia patients before each transfusion episode to detect early alloimmunization. The medical records of all thalassemia patients treated at our institution from 2004 to 2007 were reviewed to determine the significance of the high rate of positive DATs (52.5% of 80 patients). The majority of IgG-reactive DATs were associated with a nonreactive eluate (65.4% of 286 eluates performed). A positive DAT was significantly associated with splenectomy (χ² = 15.4; p < 0.001), elevated IgG levels (χ² = 26.8; p < 0.001), HCV (χ² = 20.7; p < 0.001), and warm autoantibody (χ² = 5.87; p = 0.03). Multivariate analysis revealed that only HCV (OR, 5.0; p = 0.037) and elevated IgG levels (OR, 9.0; p = 0.001) were independently associated with a positive DAT. Alloimmunized thalassemic patients were more likely to have a positive DAT than nonalloimmunized patients, but this association was not significant (OR, 2.2; p = 0.11). A positive DAT did not correlate with decreased response to transfusion, RBC survival, hemolysis, or increased transfusion requirements. Only two cases of early alloimmunization were detected by DAT among 288 DAT-positive samples studied during 4 years. This study demonstrated that the routine performance of DATs on pretransfusion specimens in thalassemic patients has limited clinical utility, and the elimination of this test will improve turnaround time and decrease costs.

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    ABSTRACT: In the absence of curative treatment, such as stem cell transplant, regular transfusions remain the mainstay of therapy for individuals with thalassemia major, a syndrome that results from marked ineffective erythropoiesis and the resultant anemia. The primary objectives of transfusion therapy are twofold: to suppress ineffective erythropoiesis and to ensure appropriate growth and development through childhood. In practice, a number of different transfusion protocols are in use across the developed world, with on-demand transfusion still being the paradigm in most of the developing world with limited resources. To investigate perceived differences in transfusion practice, a self-reported electronic survey was disseminated to eight US thalassemia treatment centers in February 2011. The survey was divided into sections ranging from laboratory and clinical practices to emerging transfusion-transmitted diseases. The survey response rate was 100%. The total number of transfused patients was 411. One-hundred percent of institutions used leukoreduced blood. No centers routinely provided cytomegalovirus-seronegative red blood cells (RBCs). Half the centers provided irradiated RBCs; only one routinely provided washed RBCs, and none transfused RBCs of defined storage age. Seventy-five percent of centers routinely phenotyped thalassemia patients' RBC antigens; 50% prophylactically matched for Rh and K antigens. The frequency of antibody investigations varied widely, and 25% of centers routinely medicated patients before transfusion. Eight thalassemia centers in the United States were surveyed to determine the uniformity of transfusion practice. The variability of the results was surprising. Consequently, we performed a literature review and propose an evidence-based protocol for routine transfusion therapy for patients with thalassemia.
    Transfusion 02/2014; 54(7). DOI:10.1111/trf.12571 · 3.23 Impact Factor


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