A rapid method of chromosome identification in interphase is -

"FISH can be used in interphase cells to determine the chromosome number of one or more chromosomes as well as to detect some specific chromosome rearrangements that are characteristic for certain cancers. The primary advantage of interphase FISH is that it can be performed very rapidly if necessary, usually within 24 hours, because cell growth is not required. A good example is the Aneuploid Screen test which is performed on amniotic fluid cells when there is a strong clinical indication for one of the common trisomies. The sample nuclei are denatured and hybridized with DNA probes for chromosomes 13, 18, 21, X, and Y and results usually obtained within 24 hours. Routine Cytogenetics is included with an Aneuploid Screen to confirm the results or detect any abnormalities not detected by interphase FISH".