Cytogenetic Investigations

Introduction

Cytogenetic investigations are performed on a wide range of referrals for the investigation of structural and numerical chromosome abnormalities and utilise a variety of laboratory techniques. Samples follow a particular testing pathway according to the referral reason and, in some cases, in response to the results of preliminary tests.

Chromosome analysis and Fluorescence In Situ Hybridisation (FISH) are used as front line tests to detect balanced structural chromosome rearrangements such as translocations and inversions, to investigate sex chromosome abnormalities or mosaicism. They may also be used for some family studies or as secondary tests to aid interpretation of other investigations.

Referral information

We accept blood samples for cytogenetic investigations from babies with ambiguous genitalia, suspected aneuploidies (trisomy 21, trisomy 13 or trisomy 18), for confirmation of a chromosome abnormality detected prenatally or for suspected sex chromosome aneuploidy. We also accept referrals from couples who are undergoing tests for infertility (IVF couples, azoospermic males) and patients with problems of sexual development, delayed/premature puberty or premature ovarian failure. We accept referrals for follow-up studies after the detection of a chromosome abnormality either in another family member or following a pregnancy loss. We also accept referrals for patients with a family history of a balanced rearrangement (inversion, insertion or translocation). Samples from babies under the age of three months and from expectant couples are classed as urgent samples (see reporting times).

We accept skin punch biopsy samples from patients referred with suspected mosaicism (e.g. Hypomelanosis of Ito or suspected Pallister-Killian syndrome). Skin biopsies should be taken from two areas for mosaicism studies.

Price & reporting times

NHS referrals to this service are paid for where there is an existing specialist commissioning contract for genetic testing. In other cases please contact the lab for prices. The requirements for postnatal samples are a blood sample in Lithium heparin.

Test Price (£ ex VAT) TRT *
Urgent postnatal blood sample POA 14 cd
Routine postnatal blood sample POA 28 cd
Solid tissue sample POA 28 cd

Test validation & quality assurance - information for users

Chromosome analysis cannot detect chromosome deletions/duplications/ rearrangements below 5Mb in size. Conditions associated with chromosome abnormalities below this resolution are tested by microarray or FISH.

Sample requirements

5ml Lithium Heparin blood sample (1-2ml volume sufficient for younger/difficult to bleed patients)

Skin biopsies – 1-2cm3 full skin depth transported in transport medium or sterile saline.

Referral guidelines

Please see our referral guidelines for more information.

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