FISH

Fluorescence in situ hybridization (FISH) aids in the detection of chromosome abnormalities that are below the level of resolution of conventional cytogenetics. FISH studies permit the examination of large cell populations allowing the detection of low level mosaicism for an abnormal clone. FISH can detect cryptic or variant rearrangements involving specific chromosome regions. FISH can often be performed on uncultured cells. Thus, even if attempts to culture the cells for routine cytogenetics have failed, FISH can often be performed to aid diagnosis.