What other regions could routinely be tested for in HLA?

Some clinicians would like to test to see if it is possible to match for alpha-3 domain of HLA proteins. Exon 4 and Exon 3 of Class I and Class II genes encode alpha-3 polypeptides, respectively (2x high resolution). If alpha-3 regions are not matching but ARS regions match, if that donor is the best available donor otherwise, he/she could be selected for blood stem cell donation.