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About our cytogenetics service
Scientist in Charge:
Bridget Manasse (01223 348710)
The East GLH cytogenetics laboratory works in partnership with HODS performing karyotyping using G-banding, FISH (Fluorescence in situ Hybridisation) and SNP array, and the results are integrated with other testing modalities by HODS.
Enquires about samples, turn-around-times, and availability of results should be addressed to cuh.eastglh-haemonc-cyto@nhs.net. Please see also the GLH website: https://www.eastgenomics.nhs.uk/
Karyotyping using G-banding
Karyotyping using G-banding is performed on the metaphase spreads of cells cultured from bone marrow aspirate samples or peripheral blood collected in sterile bone marrow transport medium (available from the laboratory) or Lithium Heparin.
This identifies chromosomal changes, which can be associated with a wide variety of haematological disorders and can be important for classification of the disease and give a guide to disease prognosis.
Single Nucleotide Polymorphism (SNP) array
Single Nucleotide Polymorphism (SNP) array is usually performed on DNA obtained from the aspirate sample, although if not available peripheral blood may be used. SNP arrays are particularly useful to detect copy number changes at a higher resolution than a conventional karyotype and were previously termed “molecular karyotype”. It is also useful to detect copy number neutral loss of heterozygosity which is not seen by G-banding, although fully balanced translocations are not detected using this technology. The sensitivity is approximately 10-20% and the test can be used where conventional karyotyping has failed.
Currently we use SNP arrays in the following cases:
Acute lymphoblastic leukaemia
Aplastic anaemia and PNH
Myelodysplastic neoplasms
Where G-banding has failed for sample/technical reasons, but full chromosomal analysis is required
Karyotyping using G-banding is performed on the metaphase spreads of cells cultured from bone marrow aspirate samples or peripheral blood collected in sterile bone marrow transport medium (available from the laboratory) or Lithium Heparin.
This identifies chromosomal changes, which can be associated with a wide variety of haematological disorders and can be important for classification of the disease and give a guide to disease prognosis.
Fluorescence in situ hybridisation (FISH)
Fluorescence in situ hybridisation (FISH) identifies specific genetic changes using fluorescently labelled chromosomal probes. FISH can be performed as the primary genetic test, e.g. as a screening test for recurrent cytogenetic abnormalities in a suspected disease, in diseases that cannot easily be cultured (e.g. CLL), or when cytogenetic culture for karyotype analysis fails, in order to confirm or exclude specific cytogenetic abnormalities e.g. BCR::ABL1 rearrangement in CML. Cytogenetic remission of previous abnormalities post therapy is assessed by FISH, and it is used to confirm relapse of disease.
FISH can be performed on metaphase or interphase cells on cultured blood or bone marrow, and on interphase cells from blood and bone marrow smears, cytospin preparations from CSF or pleural effusions and tissue sections.
| Cytogenetics | |
|---|---|
| Specimens required | Karyotyping: Bone marrow aspirate (1–2 mL) in bone marrow transport medium containing RPMI medium, heparin, and antibiotics (available from the laboratory on request). If unavailable, samples should be placed in lithium heparin. FISH: Ideally performed on EDTA. In certain instances, FISH may be performed on formalin-fixed, paraffin-embedded tissue sections. Please call the laboratory to arrange for these to be done, and for further details on sample requirements. SNP arrays: EDTA is preferred, although bone marrow transport medium may also be used. DNA obtained from formalin-fixed material is not suitable for arrays. |
| Reporting | The cytogenetics report will provide the karyotype of the cell population analysed and/or abnormalities detected by FISH. An overall conclusion and interpretation (including prognostic significance where known) will be given in the primary report and this will be interpreted in light of the other findings in the integrated report. |