Cytogenetics is the study of chromosomes and the related disease states caused by numerical and structural chromosome abnormalities. A several cell or tissue types can be useful to obtain chromosome preparations required in the assay. These samples include peripheral blood, bone marrow, amniotic fluid, and products of conception. Although specific techniques differ according to the type of specimen used, the basic method for obtaining a chromosome preparation is similar.
Fluorescent IN SITU Hybridization (FISH) is a relatively new technology utilizing fluorescently labeled DNA probes to detect or confirm gene or chromosome abnormalities that are generally beyond the resolution of routine Cytogenetics. The sample DNA is first denatured, a process that separates the complimentary strands within the DNA double helix structure. The fluorescently labeled probe of interest is then added to the denatured sample mixture and hybridizes with the sample DNA at the target site as it reforms itself back into a double helix. The probe signal can then be seen through a fluorescent microscope and the sample DNA scored for the presence or absence of the signal.