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Tests for adults

Sample requirements

Samples should ideally be sent to the Cytogenetics Department on the same day/next day. Where a delay is inevitable, such as over weekends, please store the sample in a refrigerator before sending on the next working day but please DO NOT FREEZE. Lithium heparin and EDTA tubes are suitable for cytogenetic testing depending on the test required, please see below, samples in other tubes will be rejected. For sample labelling, sample tube guide and completion of referral form criteria please see referral requirements.

 

Karyotype and FISH

Please send a 2-4ml blood sample well-mixed in a lithium heparin (green cap) tube. You may also wish to refer a POC/placental sample for recurrent pregnancy losses, please see solid tissues.

Targeted G-banding

Targeted G- banding will be performed if a known chromosomal rearrangement is being investigated e.g. A known familial rearrangement; aneuploidy detected by FISH/QF-PCR/array testing; a particular pattern of CNVs detected by array testing suggestive of a balanced parental rearrangement.

Chromosomal Microarray

Please send a 3-5ml blood sample, well mixed, in EDTA to Cytogenetics. Only one EDTA tube is required. 

 

Fanconi Anaemia

Fanconi Anaemia referrals should be sent to Sheffield Diagnostic Genetic Services. Please see SDGS website for details.

 

Acceptance and rejection criteria

Lithium heparin is the preferred tube for karyotype testing. Bloods received in EDTA will be processed but the quality may be compromised. Bloods received in any other tube will not be processed. For microarray testing, blood in any tube other than EDTA will not be processed. The preferred volume is larger than 1ml, however for smaller volumes processing will be attempted but the test may be unsuccessful.

For urgent referrals and unrepeatable samples, if blood samples are received clotted or haemolysed, processing is usually attempted, however this may compromise the success or quality of the test. For a routine referral, the sample may be rejected and a repeat sample requested.

Referral categories and tests

Karyotype

  • Recurrent (3 or more) pregnancy losses (blood samples from both partners, where no POC is available/unsuitable - no fetal parts). Please explicitly state on the referral card the referral criteria. 
  • Male patients with: azoospermia, oligospermia or asthenospermia
  • Male patients with features of Klinefelter syndrome
  • Couples experiencing prolonged infertility or sub fertility (blood samples from both partners)
  • Female patients with primary or secondary amenorrhoea or features suggestive of Turner syndrome
  • Female patients with premature ovarian failure/premature menopause
  • Family history of chromosome abnormality or rearrangement (including those detected antenatally)
  • Patients with family members with features suggestive of a chromosome abnormality
  • Pregnancy loss/termination with abnormality detected on scan (blood samples from both partners)
  • Features of chromosome instability
  • Inheritance studies following tests on other family members

Please note, if a patient or partner is pregnant, or there is another clinical need for urgency please indicate this on the referral form.

 

FISH - Fluorescence In Situ Hybridisation

We have FISH probes available for some microdeletion syndromes. For specific exclusion of these syndromes please indicate on the referral card which syndrome is to be tested for. For other FISH tests please contact the department to discuss your requirements. Please note, that microarray analysis for probands suspected to have a microdeletion syndrome is a more appropriate test. Please see neurodevelopmental disorders.

 

Chromosomal Microarray

Microarray is undertaken in place of karyotype analysis where the patient meets some of the following criteria:

  • Developmental delay or learning delay
  • Learning disability
  • Facial dysmorphism or congenital abnormalities

As well as the above categories, microarray may also be requested for inheritance studies following tests on a family member. Please refer to the link for neurodevelopmental disorders. For other referral reasons appropriate for microarray testing, see the National Genomic Test Directory.   

 

Limitations

Please see our limitations of testing page.

 

Storage and further testing

Fixed material from adult referrals is kept for 6 months from receipt date of the sample. After this time cases with a normal karyotype are discarded; cases with a structural chromosome abnormality are stored for 5 years. Subsequent genetic testing can be requested at any time within these periods but may not be possible depending on the quality of the material available.

Page last updated 02/05/2024. Please note that if printed, the information is only valid on the day of printing.