The CHD1/D5S23,D5S721 FISH probe set is designed to detect copy number changes in the region of the human CHD1 gene located on chromosome band 5q15-21 and the region around STS marker D5S23 and D5S721. The kit contains two differentially labeled probes: A Locus Specific Probe (LSP), CHD1, covers a chromosomal region which includes the entire CHD1 gene. The other probe, LSP D5S23,D5S721, covers the chromosomal region between the STS marker D5S23 and D5S721 and the region upstream and downstream of the two markers.

The probe is labeled with CytoOrange and CytoGreen. CytoOrange is a fluorophore with an excitation peak at 551 nm and emission peak at 575 nm, giving it an orange fluorescent signal with an appropriate filter; CytoGreen has an excitation peak at 495 nm and emission peak at 518 nm, giving it an green fluorescent signal with an appropriate filter.