Test Details: Fluorescence in situ hybridization (FISH) is a sensitive method to detect smaller genomic changes associated with various haematological malignancies and solid tumours. The deletions of the long arm of chromosome 6 are non-random cytogenetic anomalies found in 3 to 7% of cases with chronic lymphocytic leukaemia (CLL). CLL with deletion of 6q is associated with unfavourable prognosis.