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 334Kb) 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)	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
  	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)
  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

• Consent form for adults (PDF 35Kb)
• Consent form for adults unable to consent (PDF 52Kb)

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.

• Huntington's disease diagnostic testing form (Word 21Kb)
• Presenilin 1 disease diagnostic testing form (not pre-symptomatic testing) (Word 26Kb)
• DRPLA diagnostic testing form (Word 21Kb)

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