These fluorescence in situ hybridization (FISH) probes are intended to detect copy number of chromosomes 13, 16, 18, 21, and 22.

The Vysis MultiVysion PB Multi-color FISH Probe Kit consists of a 5-color, 5-probe mixture of DNA probe sequences homologous to specific regions on chromosomes 13, 16, 18, 21, and 22. Each of the probes is directly labeled with one of the Vysis fluorophores. The probe mixture consists of:
 

• LSI 13: DNA probe spanning the RB1 gene (13q14) labeled with SpectrumRed
• CEP 16: D16Z3 satellite II DNA probe (16q11.2) labeled with SpectrumAqua
• CEP 18: D18Z1 alpha satellite DNA probe (18p11.1-q11.1) labeled with SpectrumBlue
• LSI 21: DNA probe corresponding to loci D21S341, D21S342, D21S339, ERG, and D21S338 (21q22.13-21q22.2) labeled with SpectrumGreen
• LSI 22: DNA probe corresponding to the BCR locus (22q11.2) labeled with SpectrumGold.

Fluorophore‑labeled human placental DNA (SpectrumAqua) is also included in the probe mixture to provide a nuclear stain that does not interfere with the probe fluorescent signal. Unlabeled blocking DNA is also included with the probe to suppress sequences contained within the target loci that are common to other chromosomes.

The LSI 13 probe target is approximately 422 kb in length (chr13:47633474-48055374; February 2009 Assembly UCSC Human Genome Browser). The LSI 21 probe target is approximately 350 kb in length (chr21:39491467-39841748; February 2009 Assembly UCSC Human Genome Browser). The LSI 22 probe target is approximately 287 kb in length (chr22:23345111-23632068; February 2009 Assembly UCSC Human Genome Browser)..