Cytogenetic analysis is an important tool in preand postnatal diagnosis as well as cancer detection. In a traditional cytogenetic technique known as karyotyping the metaphase chromosome spreads are prepared on a glass slide and stained with a Giemsa stain. The stain reveals a specific banding pattern for each chromosome – a chromosome bar code. Karyotyping is often supplemented by the molecular cytogenetic technique Fluorescent In Situ hybridization (FISH), which requires the use of fluorescently labeled DNA probes to target a specific chromosome region. In FISH the chromosome preparations (metaphase spreads or interphase nuclei) are heat denatured, followed by application of the probe and hybridization at 37 °C. FISH can be performed on interphase nuclei on non-cultured cells in less than 24 hrs, but the chromosome structure cannot be visualized. On the other hand, metaphase FISH has the advantage of visualizing the entire karyotype at once and can detect potential abnormalities at a high resolution. But, the long analysis time and culturing required for metaphase FISH are important disadvantages.