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INTRODUCTION OF FLOW CROSSMATCH AND FLOW PRA TESTS FOR LIVE DONOR PRE-TRANSPLANT ROUTINE IN A MEDIUM-SIZE TRANSPLANT PROGRAM.
Sara Joseph, MLT, LT, Barbara Bagnerol, MLT, LT, Linda McEneny, RT, Merl D
Souza, MLT, LT, Terri-Lynne Oakley, RT and Denis P. Snider, PhD. Hamilton ON, Canada, Hamilton Health Sciences, L8N 4A6, Hamilton Regional Lab Med Program and Hamilton ON, Canada, McMaster University, L8N3Z5, Pathol.and Mol. Med..
Flow cytometric testing for crossmatch and anti-HLA antibody screening (PRA) is rapidly becoming the method of choice for pre-transplant testing in kidney tranplantation. The high cost of instrumentation and technologic expertise have been barriers for some smaller transplant centers. We devised a simplified protocol for flow crossmatch with FlowPRA testing for use in our center were live donor transplants generally number less than 40 per year, but are currently increasing in demand. The work presented will be our experience in introduction of the tests, the simplifications we devised to reduce cost and maintain high technical sensitivity and reproducibility. We will present data directly comparing flow crossmatch results with our typical CDC(NIH-long) crossmatch technique, both from data during development and after implementation. As found by other groups, we found a substantive increase in B cell positive flow crossmatch, compared to CDC crossmatch. The FlowPRA test was then found essential to rule out false positives. Data will also be presented concerning problems and solutions we managed in development of the flow crossmatch and flow PRA. Among these will be discussion of determination of historic ranges and values for postitive-negative cutoff in flow crossmatch, when reliance on reproducible instrument acquisition is crucial. The problem of altered autofluorescence of non-specific signal on B lymphocytes from older samples has been addressed. Control beads and interpretation of weak positive signals in FlowPRA will also be discussed.