BCR-ABL is a fusion gene formed by the rearrangement of breakpoint cluster region (BCR) on chromosome 22 with the ABL protooncogene on chromosome 9 leading to the formation of Philadelphia chromosome. This rearrangement is seen in almost 95% patients with CML. The Quantitative assay helps in the management of the disease and monitors effect of therapy. This test detects Major, Minor and Micro BCR-ABL translocation.