CAP TODAY Pathology/Laboratory Medicine/Laboratory Management
Kevin B. O’Reilly
February 2014—What would you give for a little more time? Take a vital task that you do every day, every week, or every month, and do it about three times faster—with no effect on the quality of the outcome. No, this is not another comfort-food recipe from Rachael Ray’s best-selling series of 30-Minute Meals cookbooks. This is the story of how a growing number of histocompatibility laboratories are optimizing a test that can detect low concentrations of donor-specific human leukocyte antigen antibodies and help avoid post-transplant organ graft failure.
The flow cytometric crossmatch is one of several tests that histocompatibility labs can use, after HLA typing is done, to determine the risk of hyperacute rejection or other early graft failure. It is a final compatibility check before giving the transplant team the green light. The test, which reveals how serum from the recipient reacts against donor lymphocytes, is more sensitive than cytotoxicity-based methods. A positive flow cytometric crossmatch—even in the presence of a negative complement-dependent cytotoxic crossmatch or a negative antihuman globulin-augmented cytotoxic crossmatch—is a strong predictor of graft rejection.
Use of the flow cytometric crossmatch has grown, according to the CAP. Between 2002 and 2007, there was a 7.1 percent growth in how often transplant labs used flow cytometry in crossmatch proficiency tests for class one antibodies, and a 20.6 percent jump in their use for class two antibodies (McGowan. Increased utilization of flow cytometry in HLA crossmatching reported in CAP proficiency testing. NewsPath. Nov. 12, 2008).
Of more than 130 labs participating in HLA antibody proficiency testing conducted by the American Society for Histocompatibility and Immunogenetics in 2013, about 70 percent performed the flow cytometric crossmatch. With the flow method becoming mainstream, there is growing interest in getting the assay completed more quickly so that physicians and patients get the answers they need to take action in the time-sensitive world of transplant medicine.