A Questionnaire Survey of HLA Crossmatch Tests in Korea (2015)

ABSTRACT

BACKGROUND: We carried out a questionnaire survey for laboratories performing human leukocyte antigen-crossmatch (HLA-XM) to provide a basis for laboratory standardization of HLA-XM tests in Korea. METHODS: The questionnaires were distributed to 51 HLA laboratories participating in the HLA-XM part of the HLA proficiency survey program organized by the Korean Society for Laboratory Medicine and replies from 50 laboratories were analyzed. The questionnaires included following items 1) HLA-XM methods performed and annual number of tests, 2) types of the specimen and lymphocyte separation methods, 3) test procedures and reagents for complement-dependent cytotoxicity crossmatch (CDC-XM) and flow cytometry crossmatch (FCXM). RESULTS: The number of laboratories performing anti-human globulin (AHG) CDC-XM (47/49, 96%) and FCXM (30/50, 60%) was considerably increased compared to the 2005 survey (AHG CDC-XM, 35/43, 81%; FCXM, 7/44, 16%). As for the annual number of XM tests, more than 50% of the laboratories were low volume laboratories performing ≤50 tests, and only 10% of the laboratories were performing >500 tests. For cell isolation methods, negative selection was used by 43% (21/49) of laboratories performing CDC-XM. Number of cells reacted per 1 µL of serum varied among different laboratories in both CDC-XM (1,000–8,000) and FCXM tests (1,300-20,000). For the interpretation of FCXM, log fluorescence ratio (26/30, 87%) was more commonly used than channel shift values (5/30, 17%). CONCLUSIONS: Considerable variation is noted in both CDC-XM and FCXM methods performed by different laboratories. A continuous effort for laboratory standardization is needed to reduce inter-laboratory variation in the HLA-XM test results.