Every 3 months (± 1 month) for the first year, then every 4-6 months after that until 3 years from the start of therapy, and then at any time the doctor thinks it is needed after that, you will have a bone marrow aspiration performed to check the status of the disease. This sample will also be used for cytogenetic testing and may also be used to measure how the level of BCR-ABL in your bone marrow.