Cytogenetic investigations of patients with haematological malignancies screen for chromosome abnormalities to elicit specific information about a patient’s disease, their prognosis and to assist in devising the most suitable management strategy. Subsequent analysis of follow up samples is used to monitor the effects of treatment and define disease remission.
Appropriate referral categories include (but are not limited to):
• Acute myeloid leukaemia (AML)
• Acute lymphoblastic leukaemia (ALL)
• MyeloproliferativeNeloplasm (MPN)
• Chronic myeloid leukaemia (CML)
• Myelodysplastic syndromes (MDS)
For some haematological malignancies gene or chromosome-specific fluorescence in-situ hybridization (FISH) analysis of dividing or non-dividing cells may be appropriate either in addition to, or instead of, conventional cytogenetic analysis. We will decide on the most appropriate test(s) on a case-by-case basis, even if this is not specified on the referral form. More detailed information on disease-specific FISH assays is accessible under “FISH tests for Haematological Neoplasms”.
Occasionally samples fail to yield metaphase cells for chromosome analysis. If relevant, FISH may be performed in such cases to investigate common abnormalities associated with a particular disease type.
Sample Required See notes section
Sample Volume Samples would not be rejected on the basis of small volume, however, 5 mL is ideal.
Turnaround Time Urgent referrals (acute leukaemia and CML) 95% should be reported within 10 calendar days. • Rapid test by FISH 95% should be reported within 3 working days. • Routine referrals 95% should be reported within 21 calendar days
Bone marrow in cytogenetic transport medium (preferred) or lithium heparin is usually the sample of choice, but peripheral blood may be suitable if there are circulating blasts and/or a high white blood cell count or, if necessary, for confirmation of constitutional karyotype as part of leukaemic work up. Peripheral blood in EDTA is only suitable for samples requiring FISH tests alone. Samples which are non-sterile, clotted or collected in sodium citrate, fixative or saline are not suitable. To ensure appropriate analysis and interpretation it is important to provide clear and concise clinical information.