Human Leukocyte Antigen Typing Proficiency Surveys in Korea, 2005-2006

Background : To monitor the performance of histocompatibility testing laboratories, HLA proficiency survey in Korea has been conducted biannually since 1996. In this report, we summarized the results of the surveys performed in recent two years (2005-2006). Methods : A total of four proficiency surveys were performed, in which 59-61 laboratories participated. Each survey included three tests for HLA class I (serology and DNA) and class II (DNA) typing and six tests for HLA crossmatch. Results : The overall concordance of serologic typing was 98.9% (355/359) for HLA-A, 97.5% (350/359) for HLA-B, and 94.7% (337/356) for HLA-C. The antigens assigned correctly by less than 95% of the participating laboratories were A26 (93.8%), B38 (94.2%), Cw3/Cw10 (90.9%), Cw6 (94.4%), and Cw8 (74.3%). The overall concordance rates of DNA typing were 99.6% (533/535) for HLA-A, 99.8% (539/540) for HLA-B, and 100% (392/392) for HLA-C. Correct assignment of HLA-DRB1 and -DQB1 was reported by 99.2% (98.1-100%) and 96.7% (88.9-100%) for the generic level and 100% and 95.8% (75-100%) for the allelic level, respectively. On the average 3.8% (0-7.7%) of the total laboratories showed unacceptable results in the crossmatch tests. Conclusions : The rates of correct antigen identification and of unacceptable crossmatch were similar to those of previous surveys, which were considered satisfactory. The Korean proficiency survey program may have contributed to a high quality of HLA tests today and should be continued for further improvements of the tests tomorrow.