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Sending samples for genetic testing

 

This page contains information for medical professionals wishing to send samples to us for genetic testing.

Sending samples

Please complete a specimen form| (PDF 28Kb) and send your sample by first class post or courier to:

Genetics centre
5th floor, Tower Wing
Guy’s Hospital
Great Maze Pond
London SE1 9RT

Please make sure that:

  • the courier has been told to send samples to the above address, not to the main hospital reception
  • all samples are sent according to the Transport of Clinical Specimens Regulations:

1) IATA Packaging Instructions 650 (PI 650) for transport of clinical specimens by Royal Mail or courier require a "Triple Layer" system of packaging, which comprises a primary leak proof receptacle within a secondary leak proof receptacle contained in an outer rigid package.

2) There should be sufficient absorbent material between the primary and secondary packing to absorb all liquid and the primary or secondary packing should be strong enough to withstand a 95 KPa pressure differential and to withstand a drop of 1.2 metres.

3) The paperwork must be enclosed between the secondary and outer packaging. The package should be clearly labelled Diagnostic Specimen or Clinical Specimen.

  • Chromosome testing and FISH

    Sample type

    Sample size

    Instructions for sending sample

    Blood in Lithium Heparin (karyotyping, breakage studies and FISH)

    In EDTA (aCGH, MLPA)

    5 ml in Lithium Heparin (2ml from babies)

    5ml in EDTA

    Do not spin down before sending. Do not freeze. Samples should arrive within 72 hours (preferably 24 hours) of sampling.
    Tissue   Solid tissue samples should be sent in a dry, sterile, air-tight container without fixatives or preservatives. Skin biopsies or small samples of other solid tissue should be placed in a standard tissue culture medium.

    Prenatal diagnosis

     

    Chorionic Villus (or Placental Biopsy) in culture medium (please contact the laboratory).

    Amniotic fluid: in a sterile Universal container.

    Fetal blood - in Lithium heparin

    30mg

     

    12-15ml

     

     

    2ml

    Please notify laboratory before sending any samples.

    All prenatal samples must arrive in the laboratory on the day of sampling, preferably before 4pm. Please avoid sending chorionic villus samples on a Friday.

    All Prenatal samples are first processed by cytogenetics. If DNA testing is required an appropriate sample will be sent on to the DNA lab. If a suitable amount remains chromosome analysis will be performed on all prenatal samples unless otherwise requested.

  • DNA testing

    Sample type Sample size Instructions for sending sample

    Blood in EDTA

    5ml from adults

    2-3ml from children

    Do not spin down before sending. Do not freeze. Samples should arrive within 24 hours of sampling.
    Tissue   Tissue samples (eg fetal tissue) should be sent in a dry, sterile, air-tight container without fixatives or preservatives, unless otherwise indicated

    Prenatal diagnosis

    Chorionic villus biopsy is preferred, but amniotic fluid can be accepted.

    30mg

    CVS

     

    12-15 ml Amniotic fluid

    All prenatal samples must arrive in the laboratory on the day of sampling, preferably before 4pm. Please avoid sending chorionic villus samples on a Friday.

    All Prenatal samples are first processed by Cytogenetics. If DNA testing is required an appropriate sample will be sent on to the DNA lab. If a suitable amount remains chromosome analysis will be performed on all prenatal samples unless otherwise requested.

  • Biochemical testing

    Sample type Sample size Instructions for sending sample

    Blood in Lithium Heparin

    galactosaemia

    other single enzyme tests 

    grouped enzyme tests (lysosomal screening)

    Tays Sachs testing

    2 ml

    5 ml

    10 ml (adult or child)

    Do not spin down before sending. Do not freeze. Samples should arrive within 24 hours of sampling.

    Skin biopsy

    Amino acid and organic acid disorders and some lysosomal and peroxisomal disorders.

      Please send sample in a sterile bottle containing tissue culture medium. Please send at room temperature, to arrive within 24 hours. DO NOT FREEZE.

    Hair roots

    For Fabry disease carrier testing.

      Patients should usually be referred to the Genetics Clinic for an appointment. Laboratory can supply instructions on taking and transporting sample if necessary.

    Liver biopsy

    For some urea cycle disorders.

     

    Sample should be snap-frozen in liquid nitrogen and transported in solid CO2.

    Please contact the laboratory before sampling takes place.

    Urine samples

    Mucoplysaccharide and oligosaccharide analysis - in a sterile container without preservative

    A random sample of 10-20 ml Can be transported to the laboratory at room temperature. If not sent immediately, sample can be frozen.

    Prenatal diagnosis

    Chorionic Villus (or Placental Biopsy) in culture medium.

    Amniotic fluid: in a sterile Universal container.

     

     

    30mg

     

    12-15ml

    All prenatal samples must arrive in the laboratory on the day of sampling, preferably before 4pm. Please avoid sending chorionic villus samples on a Friday.

    All prenatal samples are first processed by cytogenetics. If biochemical testing is required, an appropriate sample will be sent on to the biochemical genetics lab. If a suitable amount remains, chromosome analysis will be performed on all prenatal samples unless otherwise requested.

  • Reporting times

     

    Blood samples

    Prenatal samples

    Other samples

     

    Urgent

    Routine

    Cytogenetics

    Neonates

    (for management)

    QF-PCR / (rapid preliminary result) 1-3 working days

    Full karyotype:

    5-7 working days

    Other urgent bloods

    Full karyotype:
    5-7 working days  

    4 weeks

    (can vary with workload)

     

    CVS/Amnio

    QF-PCR: 95% reported within 1 working day 100% within 3 working days.

    Full karyotype: 10-14 working days

     

     

    Fetal blood

    QF-PCR / FISH: (rapid preliminary result) 1-3 working days

    Full karyotype: 5-7 working days

     

    DNA

    N/A

    Testing for specific mutations  (common mutations, or known familial mutations) 2 weeks

    Full gene mutation screen (sequencing) 8 weeks per gene

    Linkage analysis (may require blood samples from several family members) 2 weeks

    3 days (if the appropriate family studies have already been completed)

    As for blood samples

    Biochemistry

    Urgent bloods from neonatal samples for:

    Galactose-1-phosphate- uridyl- transferase

    3 days 

    Lysosomal enzyme screen 3-6 weeks

     

    Tay-Sachs carrier testing 6weeks

    CVS

    Direct enzyme testing: 2-5 days

    Confirmation on cultured villi: 2-3 weeks (not always necessary - please contact lab to discuss)  

    Amniotic fluid

    Direct metabolite testing (where appropriate) 3-7 days

    Enzymology on cultured cells: 2-3 weeks

Consent forms for patients

It is the responsibility of those requesting consent to use the appropriate consent form. Please do not send forms to the laboratory. Keep them with the patient's medical record.

If a patient is unable to consent for themselves, please obtain genetics and Trust guidance by contacting

Adults

Children

Forms for Huntington’s disease, DRPLA, and Presenilin 1 diagnostic testing

These tests can only be performed by the lab if accompanied by completed forms, which can be downloaded below.

For pre-symptomatic predictive genetic testing for any of these diseases, please refer the patient to the genetics clinic.

 

Questions about sending samples?

For more information about sending samples, visit the Viapath website| (our pathology services provider).

For more information about available tests, visit Viapath genetics|.

Questions about sending samples|.