Pcr-FISH-karyotype. There are 3 main types of genetic tests. The old standard is to take a blood sample from the hip (marrow) and grow cells to look at all the chromosomes (karyotype). It is a 'broad strokes' look but not as sensitive as the others. A fish test looks at blood cells with 'probes' to the known genetic changes (moderately sensitive) and a PCR test is a 'molecular' test of the dna (very sensitive).
Chromosome tests. For people with cml, bone marrow chromosome studies (karyotype) often show the philadelphia chromosome (a chromosome #22 that is shortened because its distal end is transferred (translocated) to chromosome 9. Antibody (gleevec) to the translocation protein is helpful and bone marrow transplant is a form of gene therapy that provides cells with normal chromsomes.