Direct, short term and/or long term cultures are used depending on clinical requirements.
Results may take from 2 days to 3 weeks for completion.
The type and duration of culture vary for the indication and specimen type.
Cytogenetic harvesting, slidemaking, banding and karyotyping are performed on all specimens. FISH or rapid molecular methods such as Quantitative Fluorescent PCR are often used to rapidly screen samples for common aneuploidies before definitive (karyotype) results are available.
Fluorescence in situ hybridisation (FISH) on metaphase spreads may increase the accuracy of cytogenetic diagnoses in some situations.
See also Fluorescence in situ hybridisation.
Microarray methods are now available in some laboratories for prenatal testing.
Microarray testing has a higher resolution for gains/losses of genetic material than conventional karyotype, but will not detect balanced chromosomal rearrangements, Microarray testing may not detect mosaic gains or losses of genetic material.