What is FISH?

FISH (fluorescence in situ hybridization) is used to detect the presence or absence of specific regions on chromosomes.

A fluorescence microscope is used to find the probes and determine the number of chromosomes present.

Typically we use either 5 or 7 probes for chromosomal aneuploidy;

- 5 probes for chromosomes X, Y, 13, 18 and 21

- 7 probes (includes the 5 above) followed by testing for chromosomes 16 and 22

Specific probes may also be used for translocations.