Direct preparation and/or short term cultures are generally used. Chronic lymphoproliferative disorders may require mitogen stimulation and 72 h culture. Solid tumour specimens may require even longer culture times depending on the tumour type.
Results may take from 2 days to 3 weeks for completion. The type and duration of culture and the culture medium used may vary for the indication and specimen type.
Cytogenetic harvesting, slidemaking, banding and karyotyping are performed on all specimens. FISH may be used to identify specific chromosomal abnormalities. See also Fluorescence in situ hybridisation.
Molecular testing based on PCR (polymerase chain reaction) is available for detection of specific chromosomal abnormalities, such as the BCR-ABL fusion gene typically seen in Chronic myeloid leukemia.
Microarray methods are used in some laboratories for oncology testing, but this is not currently widespread.
Note that for molecular testing (PCR or microarray), a sample collected in EDTA is generally required.