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The National Genomic Test Directories specify which genomic tests are commissioned by the NHS in England, to be delivered by Genomic Laboratory Hubs.

Clinical Indication ID & Name

R297

Possible structural chromosomal rearrangement - karyotype/Targeted Chromosome Analysis

Test Group

Core

Test code

R297.1

Test name

N/A

Target genes

As determined by indication

Test scope

copy number variant detection to genomewide resolution and structural variants or TCA

Test method/ technology

Karyotype/TCA

Optimal Family Structure

n/a

Eligibility Criteria

Testing Criteria
Possible structural chromosomal rearrangement requiring karyotype or targeted chromosome analysis (TCA) including one of the following:
1. Possible Robertsonian translocation, reciprocal translocation, ring chromosome or other microscopically visible structural rearrangement indicated by findings from microarray, WGS or other laboratory technique. [TCA]

2. Recurrent miscarriage (defined as three or more miscarriages) [karyotype]:
• where testing of the pregnancy loss has not been possible due to an unsuitable/failed sample e.g. no fetal material/MCC/fixed in formalin, and no previous losses have been successfully tested and reported.
Note that although parental karyotype analysis is available following a failed test, this is of limited utility and the most informative pathway is to test any subsequent pregnancy loss.
• with five or more pregnancy losses where none of the previous losses has been successfully tested and reported e.g. biochemical pregnancies, no products available for testing

3. Known familial rearrangement or a family history suggestive of familial balanced translocation. [TCA/Karyotype as appropriate]
4. Unexplained infertility prior to infertility treatment. [karyotype]
5. Patient with ambiguous genitalia potentially caused by a sex chromosome rearrangement not detectable via other tests. [TCA]
6. Egg/sperm donors prior to acceptance. [karyotype]
7. Possible sex chromosome structural rearrangement or sex chromosome aneuploidy (mosaicisim) for example Turner, variant Turner, mosaic Turner syndrome. [TCA]

To note: Application of either karyotype or Targeted Chromosome Analysis (TCA) will be directed by professional judgement, best practice recommendation, clinical context and/or the type of cytogenetic rearrangement(s) detected. Due to the nature of cytogenetic analysis, reportable cytogenetic incidental findings may be detected during TCA.

Commissioning group

Core

Overlapping idications

n/a

Address for samples/request forms

Genetics Laboratory
5th Floor Tower Wing
Guy’s Hospital
London
SE1 9RT

Contact with queries

gst-tr.southeastglh@nhs.net

Supporting documents

n/a

Education resources

n/a

Turn around times

All our turnaround times are listed on our specific turn around page https://southeastgenomics.nhs.uk/professionals/service-turn-around-times/

Consent record

See consent guidance in test request form

Sample requirements

Sample Requirements Each sample must be sent labelled with 3 patient identifiers and must state the sample type clearly on the sample container. Sample Rejection Samples may be rejected for the following reasons: 1. Samples and request form do not show at least three identical patient identifiers 2. The sample is in the incorrect collection media 3. The request form is not sufficiently completed 4. The sample is not of sufficient volume 5. The sample is too old