Fluorescence in situ Hybridization (FISH)
*Performed by affiliate laboratory
5mL peripheral blood in sodium heparin
3mL bone marrow in sodium heparin
Fixed cytogenetically prepared cells in sterile centrifuge tube with pellet visible in 3:1, Methanol:Acetic Acid
4°C to 25°C during transit, but specimens may be transported on refrigerated gel packs. Do not allow the gel pack to come in contact with the specimen. Do not freeze. Extreme temperatures should be avoided.
Clotted specimen; Specimen exposed to extreme temperature; Anticoagulant or collection vessel toxic to cells; Insufficient number of cells; Specimen exposed to fixative
Presence or absence of the microdeletion
It is recommended that all FISH studies be done in conjunction with routine cytogenetic studies. If the FISH result is normal, a chromosome analysis allows identification of more complex abnormalities.
Wolf-Hirschhorn syndrome, causing deletion of the short arm of chromosome 4, affects approximately 1 in 50,000 births.