The Class I SeCore® sequencing strategy begins with a multiplex PCR. Two fragments are amplified; one amplicon encompassing exon 2 and 3 and the other encompassing exon 4. The sequencing mixes are designed for bi-directional sequencing of each exon. The single amplification kits are available for A, B and C loci.

In addition, the B locus can be sequenced using a dual amplification method.  The B Locus, Group Specific Set kit includes two amplification mixes, each specific to a set of alleles. Heterozygous sample alleles are often amplified by different mixes and therefore are separated by this initial PCR. The resulting typing data for each separated allele is a greatly simplified homozygous electropherogram, eliminating the challenge of interpreting polymorphic positions. This strategy reduces the cis/trans ambiguities for B locus by 45%.

Group Specific Sequencing Primers (GSSPs) are available to resolve allele specific ambiguities.