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P002 The consistent inconsistency in HLA antibody testing practices: a collaboration with the Banff workgroup
Abstracts / Human Immunology 77 (2016) 40–156
P002
THE CONSISTENT INCONSISTENCY IN HLA ANTIBODY TESTING PRACTICES: A COLLABORATION WITH THE BANFF WORKGROUP D. Dadhania 1, A. Jackson 2, P. Campbell 3, L. Bow 4, K. Almeshari 5, C. Schinstock 6, L. Cornell 6, S. Bagnasco 2, E. Kraus 7, E. Cozzi 8, M. Askar 9. 1Weill Cornell Medicine -NYP, Transplantation Medicine, New York, NY, United States; 2Johns Hopkins Medicine, Transplantation Medicine, Baltimore, MD, United States; 3 University of Alberta, Transplantation Medicine, Edmonton, AB, Canada; 4Yale University, Transplantation Medicine, New Haven, CT, United States; 5King Faisal Specialist Hospital and Research Center, Transplantation Medicine, Riyadh, Saudi Arabia; 6Mayo Clinic, Transplantation Medicine, Rochester, MN, United States; 7 Johns Hopkins Medicine, Transplantation Medicine, Baltimore, MD, United States; 8University of Padua, Transplantation Medicine, Padova, Italy; 9Baylor University, Transplantation Medicine, Dallas, TX, United States. Detection of donor specific HLA antibodies (DSA) is currently an important component of the Banff criteria for diagnosis of antibody mediated rejection. There is a perception of significant variations in anti-HLA antibody (HLA-Ab) testing practices and interpretation algorithms among different laboratories. In this study, we aimed to survey large transplant centers worldwide to evaluate similarities and differences in HLA-Ab testing practices . METHOD An online survey was sent electronically to 120 histocompatibility laboratories and we received data from 72 laboratories (60% response rate). The survey focused on defining sensitization status, method of reporting HLA-Abs, and post-transplant DSA monitoring practices. Responses from laboratories that support more than 25 transplants per year were analyzed (n = 66). RESULTS: More than 80% of surveyed laboratories use Luminex based single antigen bead assay to test for HLA-Abs. In non-sensitized patients, absence of HLA-Abs was defined by screening beads (11% of labs), phenotype beads (11%) by single antigen beads (30%) and 2 different assays (48%). For sensitized patients 54% of the laboratories used a combination of assays. Definition of highly sensitized patients varied widely among labs with thresholds ranging from 30% to 80% CPRA. Fifty-five percent of the labs reported MFI values associated with HLA-Abs while 30% reported relative strength (weak, moderate, strong) of the antibody. The definition of relative strength varied among labs with MFI ranges of 500–5000 and 3000–10,000 defining weak and strong antibodies, respectively. Only 39% of the laboratories routinely evaluated sera for the presence of interfering substances/prozone effect. Only 44% of the labs routinely screened for DSA post-transplant; 24% screened only at the time of for-cause and surveillance biopsies and 9% do not monitor for DSA at all. CONCLUSION There is great variability in testing, interpretation and reporting practices among laboratories. Similarly, the definition of a highly sensitize patient varies from center to center. Lack of consistency in practices and definitions hinder our ability to compare patient outcomes from one center to another and highlights the need for standardization and evaluation of clinical relevance of different practice patterns.
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P002
THE CONSISTENT INCONSISTENCY IN HLA ANTIBODY TESTING PRACTICES: A COLLABORATION WITH THE BANFF WORKGROUP D. Dadhania 1, A. Jackson 2, P. Campbell 3, L. Bow 4, K. Almeshari 5, C. Schinstock 6, L. Cornell 6, S. Bagnasco 2, E. Kraus 7, E. Cozzi 8, M. Askar 9. 1Weill Cornell Medicine -NYP, Transplantation Medicine, New York, NY, United States; 2Johns Hopkins Medicine, Transplantation Medicine, Baltimore, MD, United States; 3 University of Alberta, Transplantation Medicine, Edmonton, AB, Canada; 4Yale University, Transplantation Medicine, New Haven, CT, United States; 5King Faisal Specialist Hospital and Research Center, Transplantation Medicine, Riyadh, Saudi Arabia; 6Mayo Clinic, Transplantation Medicine, Rochester, MN, United States; 7 Johns Hopkins Medicine, Transplantation Medicine, Baltimore, MD, United States; 8University of Padua, Transplantation Medicine, Padova, Italy; 9Baylor University, Transplantation Medicine, Dallas, TX, United States. Detection of donor specific HLA antibodies (DSA) is currently an important component of the Banff criteria for diagnosis of antibody mediated rejection. There is a perception of significant variations in anti-HLA antibody (HLA-Ab) testing practices and interpretation algorithms among different laboratories. In this study, we aimed to survey large transplant centers worldwide to evaluate similarities and differences in HLA-Ab testing practices . METHOD An online survey was sent electronically to 120 histocompatibility laboratories and we received data from 72 laboratories (60% response rate). The survey focused on defining sensitization status, method of reporting HLA-Abs, and post-transplant DSA monitoring practices. Responses from laboratories that support more than 25 transplants per year were analyzed (n = 66). RESULTS: More than 80% of surveyed laboratories use Luminex based single antigen bead assay to test for HLA-Abs. In non-sensitized patients, absence of HLA-Abs was defined by screening beads (11% of labs), phenotype beads (11%) by single antigen beads (30%) and 2 different assays (48%). For sensitized patients 54% of the laboratories used a combination of assays. Definition of highly sensitized patients varied widely among labs with thresholds ranging from 30% to 80% CPRA. Fifty-five percent of the labs reported MFI values associated with HLA-Abs while 30% reported relative strength (weak, moderate, strong) of the antibody. The definition of relative strength varied among labs with MFI ranges of 500–5000 and 3000–10,000 defining weak and strong antibodies, respectively. Only 39% of the laboratories routinely evaluated sera for the presence of interfering substances/prozone effect. Only 44% of the labs routinely screened for DSA post-transplant; 24% screened only at the time of for-cause and surveillance biopsies and 9% do not monitor for DSA at all. CONCLUSION There is great variability in testing, interpretation and reporting practices among laboratories. Similarly, the definition of a highly sensitize patient varies from center to center. Lack of consistency in practices and definitions hinder our ability to compare patient outcomes from one center to another and highlights the need for standardization and evaluation of clinical relevance of different practice patterns.
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