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FISH analysis for Chronic Lymphocytic Leukaemia / small lymphocytic leukaemia

Category Specialist Integrated Haematological Malignancy Diagnostic Service (SIHMDS) >> Cytogenetics
Test background

FISH involves the application of fluorescent DNA probes specific to genes or genetic regions of interest that highlight abnormalities involving these regions.

Clinical Indications

In CLL/SLL, a panel of FISH probes is applied at diagnosis to identify common genetic abnormalities that are known to be strongly associated with prognosis in this disease and may assist in devising the most suitable management strategy.

The CLL FISH panel includes the following probes:

TP53  17p13
ATM 11q22

Chromosome 12 centromere

In cases of uncertain diagnosis, a probe for IGH may also be applied if it is deemed appropriate.

It may be appropriate to repeat the CLL FISH panel after treatment to assess response or to investigate disease progression.

Reference range


Sample & container required 3-5mls peripheral blood in lithium heparin
2-3mls Bone marrow in lithium heparin

EDTA PB and BM samples (>1ml) are acceptable for FISH only studies as appropriate. Please note the laboratory does not provide transport medium. Samples sent in transport media from an external laboratory containing Lithium heparin will be accepted if no other media available
Sample volume Samples would not be rejected on the basis of small volume, however, 5 mL is ideal.
Turnaround time FISH analysis in CLL/SLL is treated as routine; 95% should be reported within 21 calendar days

If the blood counts are abnormal (high or low white cell count) the volumes of BM/PB requested can be adjusted accordingly.

Delayed samples:
Samples should arrive in the laboratory as soon as possible after sampling. Samples delayed in transit may yield poor quality or failed results.