The human T-cell receptor alpha/delta (TCRAD) locus at chromosome 14 consists of 127 genes. These genes are devided into 57 variable (TCRADV) genes, 3 diversity (TCRADD) gene segments, 65 joining (TCRADJ) gene segments, and 2 constant (TCRAC and TCRDC) genes. The TCR locus spans a region of ~1 Mb on chromosome 14 band q11. Y5419 is a probe mix based on a combination of DNA and PNA technology, and contains two ready-to-use FISH DNA probes and unlabeled PNA blocking probes. The FISH DNA probes are a mixture of a Texas Red-labeled DNA probe (TCRAD-Downstream) covering 301 kb telomeric to the TCRAD breakpoint cluster region and a fluorescein-labeled DNA probe (TCRAD-Upstream) covering 1018 kb centromeric to the TCRAD breakpoint cluster region.