The SBT (Sequencing-based typing) interface is a tool accompanying the NCBI's Major Histocompatibility Complex database (dbMHC). It identifies the allelic composition of sequence-based typing (SBT) results of cDNA or genomic sequences. Samples are compared with databases containing all known alleles for several human leukocyte antigen (HLA) and killer cell immunoglobulin-like receptors (KIR) loci. An interactive sequence viewer allows inspection of the alignments.