**4.3. Allele assignment step**

A variety of different allele assignment methods have been developed with some allele assignment software packages such as Assign (CONEXIO), OMIXON Target (OMIXON), and NGSengine (GenDX) commercially available, and others such as TypeStream (Life Technolo‐ gies) still to be made commercially available in the near future. From our knowledge, Assign and NGSengine only support NGS data obtained from the one-locus, one-tube PCR method, whereas OMIXON Target and TypeStream also support NGS data obtained by the multiplex PCR methods. However, accuracy rates of the assignment methods are not 100% with genotyping errors caused by (1) missing HLA allele sequences, (2) generation of excessive allelic imbalance (ratio of sequence read numbers of allele 1 and allele 2), and (3) interference of HLA-DRB1 genotyping by participation of sequence reads originating from highly homol‐ ogous HLA-DRB3/4/5 and other HLA-DRB pseudogenes. To avoid the errors raised in point 1, it is necessary to have a full and proper collection of all the HLA allele sequences to achieve precise HLA genotyping. In this regard, a much greater collection of high-quality full-length HLA allele sequences are expected to be obtained by way of international collaborations at the 17th IHIWS meeting in 2017 [53].
