Chronic lymphocytic leukaemia FISH panel
Also known as: CLL FISH
Test category:
Oncology - Leukaemia
Use of test
Purpose:
Changes in chromosome structure and number in leukaemic cells can provide important prognostic and therapeutic information in patients with chronic lymphocytic leukaemia (CLL). A panel of probes is used to look for the most frequent abnormalities, 13q deletion, trisomy 12, ATM deletion and TP53 deletion.
Utility:
The laboratory report defines the changes in the patient's malignant cells and relates these changes to the current management recommendations.
Ethical considerations:
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.
Methodology:
Fluorescent in situ hybridisation (FISH) analysis, using probes specific to the relevant targets. This interphase FISH test has a cut off at 5%. A low level of positive cells may be due to overlap of the two signals. Studies of normal controls indicate that this level is less than 5%. Using the TP53 probe, positivity is uncertain between 5 and 10%.
Requesting the test
Ordering:
This test is usually requested by a haematologist or oncologist.
Sample required:
0.5 mL bone marrow in transport media or 10 mL blood in lithium heparin if clinically appropriate.
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.
Turnaround time:
5 business days.
Price:
$255.
Note that in cases of relapsed or refractory CLL, TP53 deletion testing has a Medicare rebate.
Rebate:
The Medicare details, including descriptor and schedule fee, are listed under MBS item 73343.