Sending a sample to the laboratory

Samples can be sent to the laboratory for molecular genetic analysis by completion of our request and informed consent form.  

Molecular genetic testing request and consent form (PDF, 244 KB)

Non-NHS molecular genetic testing request and consent form (PDF, 517 KB)

Guidance on completing the form

Verbal requests are not accepted, so please ensure a completed request form is sent to the laboratory. Extra testing or alterations to requests should be made in writing via our contact details.

What samples should be sent?

For genetic testing please send 2 EDTA tubes. 

Minimum sample requirement = 1ml of whole blood in EDTA. Samples containing less than this may be rejected.

We can also accept saliva in Norgen collection tubes (available via Dr Homfray or the ICC Clinical Nurse Specialists).

DNA extracted from FFPE is not suitable for use with our NGS assays; please contact the lab to discuss if this is the only sample available.

Please note: we DO NOT undertake prenatal testing. 

Sending samples as DNA

For our NGS services, we recommend sending at least 3µg of DNA at a concentration of at least 50ng/µl.

Referral information

The reason for genetic testing must be clearly stated on the request form, including a summary of the clinical findings in the proband and a family pedigree if there is a positive family history of the disease. The person to be tested should be clearly marked with an arrow. For patients being referred for screening of a known familial variant, a report detailing the familial variant must also be provided. The name of the gene, transcript and variant to be tested are required for the analysis. This information is essential and it is the responsibility of the referrer to provide it.

In order for a sample to be analysed and reported, the following information must be provided on the referral form:

  • Patient forename
  • Patient surname (preferably block capitals)
  • Patient date of birth
  • NHS number (if UK)
  • Hospital number (patients of Royal Brompton and Harefield hospitals)
  • Referrer name (surname and first initial) 
  • Referrer address
  • Disease to be tested
  • Clinical details, including ethnic background of patient and family pedigree if relevant

We will not perform testing on samples that are referred with incomplete information. For efficiency, the laboratory may store the DNA or blood sample and withhold testing until more specific clinical information has been received from the requesting clinician. This will have a significant impact on the length of time taken to receive test results. Mislabelled samples may be discarded and not tested.

Unless otherwise requested, any invoices will be addressed to the referring clinician.

NHS price list including new panels and Cystic Fibrosis

Pricing can be discussed depending upon requirements – please contact us if you anticipate sending samples regularly. 

International and non-NHS patients (self-paying or privately insured)

Testing for patients outside the NHS is offered. The test cost will incur a surcharge, and payment will be requested before testing begins See our price list

For these referrals it is essential that a billing address is included with the referral details. If you wish to send a  sample from a private patient or patient outside of the NHS system or would like more information, please contact us

Sample labelling

All specimen containers must be clearly labelled.

A minimum of three identifiers are required, from:

  • Forename
  • Surname
  • Date of birth
  • One other unique identifier (hospital or NHS number)
  • Date of collection

A fully completed referral form including the identifiers that appear on the sample tube must accompany the sample. Any samples that do not meet the above labelling standards (or samples where the information is illegible) may be rejected.

Consent and sample acceptance 

All genetic testing requires consent, which is part of the request form. Samples sent without consent will not be tested.

For more information on consent please see the guidelines from the Joint Committee on Medical Genetics.

The clinical genetics and genomics laboratory adheres to Trust policies and Caldicott principles to safeguard all patient information. Diagnostic material is stored according to The Royal College of Pathologists’ guidelines.

Surplus diagnostic material from all referrals is retained for quality assurance purposes and may be used anonymously for the development of new tests unless consent for this is expressly denied on the consent form. 

Sample information

Blood samples in plastic tubes with EDTA are preferred. Other anticoagulants will impact on the testing procedure and samples may not be processed. Clotted blood is unsuitable for analysis.

Specimens should be delivered to the laboratory as soon as possible after they are taken to ensure the quality of the specimen and the success of the testing procedure. If necessary, blood samples can be left at room temperature below 22 °C or refrigerated at 4°C for up to three days without affecting quality. 

Please DO NOT FREEZE blood samples.

DNA samples can be transported at room temperature. DNA is stable for one year at room temperature if suspended in a suitable buffer.

DNA samples should be sent door-to-door to arrive as soon as possible; first-class post is satisfactory for most samples. If there is an unavoidable delay prior to dispatch, DNA samples can be stored in a refrigerator at 4°C.

DNA extracted from solid tissue, saliva or other sources, or using certain manual extraction methods, may not yield the high-quality DNA required for successful NGS. 100 per cent coverage of core genes at 20X is only guaranteed for DNA extracted from EDTA blood. 

Please contact the laboratory if you wish to send such samples. DNA extracted from FFPE tissue is currently unsuitable for processing using our NGS assays.

The quality and quantity of extracted DNA will be affected if samples are collected in incorrect containers, stored at extreme temperatures, or delayed in transit. This may result in the failure of the test. Any specimens which have been delayed in transit may not be suitable for processing and may therefore not be accepted by the laboratory.

If further testing is required on a sample already stored in the laboratory, please request this in writing.

Packaging and transportation

All clinical specimens, blood and other samples are potential biohazards and must be packaged to comply with the current regulations on the transport and postage of biological materials. Samples should be packaged so that they maintain patient confidentiality and prevent leakage and/or contamination to couriers and porters.

Diagnostic specimens should be packed in accordance with packaging instructions PI650 and UN3373 regulations. In summary, primary containers must be packed in secondary packaging in such a way that under normal conditions of carriage they cannot break, be punctured or leak their contents into the secondary packaging. Secondary packaging should then be secured in outer packaging with suitable cushioning material.

Outer packaging may consist of paper, fibreboard, plastics or metal. The sample and referral form should be sealed separately in a biohazard bag to prevent contamination of paperwork in the event of leakage. Each package must be clearly and duly marked with a label showing the characters UN3373 and “diagnostic specimen” or “clinical specimen”. For further information please see the national postal regulations.

Where samples are known to pose a specific high risk (eg. HIV, Hepatitis B/C), the nature of the risk must be clearly marked on the referral form. The referral form and specimen container should be clearly labelled (for example, with danger of infection tape) to indicate its high-risk nature. Please contact the laboratory with any queries regarding the appropriateness of sending any potentially high-risk samples.

Samples may be delivered by hospital porter, by hand, by external post (first-class only) and by courier. 

Postal address:

Clinical genetics and genomics laboratory
Level 2, Sydney wing
Royal Brompton Hospital
Sydney Street
United Kingdom

Clinical genetics and genomics laboratory

Ground floor (level 2), Sydney wing, Royal Brompton Hospital, Sydney Street, London, SW3 6NP

Telephone: 020 7352 8121 ext. 83009
Email:  or 
Opening hours: Monday to Friday, 9am - 5pm
Head of laboratory: Dr Deborah Morris-Rosendahl