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Solid Tissues

Sample requirements

Skin, placental material or products of conception

Samples should be referred in sterile isotonic saline in a sterile universal or other sealed sterile container. Fresh samples should ideally be sent to the Cytogenetics Department on the same day. Where a delay is inevitable (such as over weekends) please store the sample in a refrigerator. Please note that we cannot process samples that have been exposed to formalin.

Please avoid using large containers or sending large quantities of liquid. Ensure all containers can be securely sealed (preferably screw caps) and are appropriately packaged (see packaging guide) and that the referral form is separated from the container by a waterproof layer in case of leakage during transport.


Effusion or ascitic fluid

Samples should be referred in a sterile universal or other sealed sterile container.


Buccal smears

Samples should be applied to poly-l-lysine coated slides. Please contact the department before testing to discuss the test required. These samples can only be processed for targeted FISH.


Acceptance Criteria

In order to target limited resources, for this group of referrals the Cytogenetics Department operates an acceptance policy, please see below. For referrals which do not fulfil these criteria please contact the laboratory to discuss the test you require.


Referral categories:

  • Patients with recurrent pregnancy loss. Recurrent miscarriage defined as three or more miscarriages. These can be referred in the absence of additional features suggestive of chromosomal abnormality.
  • Foetal anomalies with a likely genetic cause detected on scan or after delivery (where there has been foetal loss, termination of pregnancy or miscarriage)
  • IUFD (only if indication of foetal abnormality with a likely genetic cause)
  • Stillbirth (only if indication of foetal abnormality with a likely genetic cause)
  • Family known to carry a chromosome abnormality
  • Fibroblast cultures requested (more information below)
  • Investigation of suspected inter-tissue mosaicism (can also be referred from live-born patients)
  • Buccal smears (targeted FISH test only). Also available for severely needle phobic patients.
  • DNA storage




Fetal skins, placenta and products of conception material will usually be processed by microarray for identification of genetic imbalance over 1Mb in size, unless otherwise indicated. In addition this test will identify triploidy and true molar pregnancies. If possible mosaicism is indicated in the referral, cultures may be established as well as DNA extracted for microarray testing. Please indicate clearly on the referral card if mosaicism is suspected, if there is a suspected fetal abnormality or if DNA storage is required.


Targeted FISH

We also offer a targeted FISH test where appropriate.



Skin samples can be sent to the Cytogenetics Department to establish fibroblast cultures which can then be forwarded for biochemical assays, molecular tests or for DNA extraction/storage. Samples for these referrals should be of full thickness. These skin samples should be accompanied by a letter to the appropriate testing centre to which cultures are to be forwarded. The letter should also include the test required and the name and address of the requesting clinician.


Reporting times

If you have a specific request for a result urgently, please contact the laboratory.

Please see our Target Reporting Times.



Please see our solid tissue limitations of testing.


Storage and further testing

DNA from samples referred for microarray testing is stored indefinitely. Any stored tissue will be kept for 1 year. Fibroblast cultures are available for 1 month after primary cultures have been forwarded as appropriate. Fixed material from samples that had been cultured for previous karyotype analysis (now processed via microarray) or fixed material for FISH is stored for at least 10 years for cases with an abnormal karyotype.

Page last updated 13/06/2022. Please note that if printed, the information is only valid on the day of printing.