Use of test
Translocations between Chromosome 9 and 22 resulting in fusion of the BCR and ABL1 genes can occur in a number of haematological malignancies, particularly chronic myeloid leukaemia (CML), and also acute myeloid leukaemia (AML) and acute lymphoblastic leukaemia (ALL). The presence of this fusion has diagnostic and therapeutic implications.
The fusion gene can be detected at very low concentrations and be a marker of therapeutic response or disease progression. This assay detects the most common BCR-ABL fusions (the M-bcr transcripts, resulting in the P210 protein product).
Presence of a BCR-ABL1 fusion gene in patients with CML is associated with response to targeted therapy by tyrosine kinase inhibitors such as imatinib, and good prognosis. It is associated with a poor prognosis in ALL or AML.
Quantitative PCR is typically used in post-treatment minimal residual disease monitoring, as it can detect the presence of a very low level of the BCR-ABL1 fusion gene. If used for post-treatment monitoring, the specific BCR-ABL fusion must be known, and must be detectable by this assay.
This is an assay for non-heritable mutations. It does not raise issues of ethics or consent that are different from most other investigations ordered in the routine care of a patient.
Quantitative Polymerase Chain Reaction (PCR) analysis to determine the level of BCR-ABL1 fusion transcript, normalised to the International Scale (IS). This BCR-ABL quantitative PCR test detects the e13a2 (b2a2) and e14a2 (b3a2) fusion transcripts (aka ‘M-bcr’ transcripts, which result in the P210 protein product). These account for approximately 95% of BCR-ABL fusions in CML. Fusions involving any other breakpoints will not be detected by this assay, and an alternative test method is required. Note that ‘uncommon’ BCR-ABL fusions are more prevalent in AML and ALL than in CML.
Requesting the test
This test is usually requested by a haematologist or oncologist.
1.0 mL bone marrow in dedicated EDTA (or 10 mL blood in dedicated EDTA if peripheral blood is used for monitoring).
To help ensure the quality of the test, a genetic test should be done with a dedicated sample whenever possible i.e. a sample collected specifically for that test rather than a sample that is used for multiple tests.
We recommend that the patient or another adult check the labelling of request forms and sample tubes.
The sample must reach the laboratory within 24 hours of collection.
Before sending the sample for testing, please contact us on tel: 1800 010 447 (Australia only) to confirm the availability of testing within this timeframe.
5 business days.
This test has a Medicare rebate which, subject to the requirements of the Medicare descriptor being met, may cover all or part of the cost.
The Medicare details, including descriptor and schedule fee, are listed under MBS item 73314.