Spectral Karyotyping (SKY)

Spectral karyotyping (SKY) permits the simultaneous visualization of each chromosome pair in a different color. Five pure spectrally distinct dyes are used either singly or in combination to create a chromosome cocktail of probes, each with a unique spectral signature for each chromosome1

 Its strength lies in its ability to define translocations, marker chromosomes, and complex rearrangements, and to reveal cryptic change; it cannot, however, detect intrachromosomal rearrangements, such as duplications, very small deletions, or small paracentric inversions1.

SKY (24 color FISH) analysis of metaphase chromosome preparations of human or mouse cells. Assay performed by trained cytogenetic technologists and reviewed by an American Board of Medical Genetics and Genomics (ABMGG) board certified or board eligible director, with results available in 14-21 days.


What it detects:

  • Microscopic (>5-10 Mb) genomic abnormalities

    • Balanced and unbalanced translocations
    • Aneuploidies

What it doesn’t detect:

  • Submicroscopic abnormalities (<5Mb genomic abnormalities)
  • Inversions
  • Duplications/deletions

When to use:

  • As an adjunct to g-banded karyotyping

    • To define complex rearrangements
    • To identify marker chromosomes
  • When publication-quality spectral karyotypes are needed



1. Arsham, M. S., Barch, M. J., & Lawce, H. J. (Eds.) (2017). The AGT Cytogenetics Laboratory Manual (4th Ed.). Hoboken, NJ: John Wiley & Sons, Inc.
Abnormal spectral karyotype of a four-way translocation.

Abnormal spectral karyotype
 of a four-way translocation.

Mouse Spectral