Cytogenetics Website
User Guide for Blood Samples
Reasons for Referral
The main reasons for referral are abnormal newborns, unexplained learning difficulties, dysmorphic children, investigation of infertility and recurrent miscarriage, parents of children with a known chromosome abnormality, follow-up from prenatal diagnosis, family follow-up and screening of patients and donors for IVF.
Referral for Prader Willi and Angelman’s Syndrome: In addition to routine cytogenetic analysis all Prader-Willi and Angelman syndrome cases are passed on to the Regional DNA laboratory to determine if there is a chromosome deletion present and to check for uniparental disomy.
Referral for Fragile X: All new cases referred with a possible diagnosis fragile X syndrome are analysed by the cytogenetics laboratory and the Regional DNA Laboratory since experience has shown that a number of other chromosome abnormalities have been detected where the screen for fragile X has been
negative. Please send two blood samples, one in lithium heparain (for cytogenetics) and one in EDTA (for DNA).
Chromosome Breakage Syndrome: Routine and specialised cultures are prepared for these cases and more blood will be required (at least 5 ml). Conditions amenable to cytogenetic analysis include ataxia telangectasia, Bloom’s syndrome, Fanconi’s anaemia and Nijmegen Breakage Syndrome. Please indicate on the request card which test is required.
Sample Required
Blood should be collected in a lithium heparin tube (orange or green top), and mixed well to prevent clotting.
More blood may be required if chromosome breakage studies are required.
Blood in EDTA will also be accepted, however many bloods sent in EDTA do not grow and those that do often require a repeat sample. Blood in other containers is not suitable for culture. Clotted blood is unsuitable for cytogenetic analysis.
Sample Transport
• Samples should be addressed to:
Cytogenetics Unit,
St. James’s Hospital
Beckett Street,Leeds
LS9 7TF
• Cytogenetic analysis requires living cells. Please ensure that the sample reaches us as quickly as possible (within 48 hours). First class post is satisfactory for non-urgent samples.
• Urgent samples should be sent by courier or taxi.
• Samples should not be frozen, exposed to excess heat or stored in formalin.
• If there is a delay in transit please store the sample at 4°C (in a refrigerator).
• Please try to avoid sending samples at weekends or bank holidays.
ALL PACKAGES MUST CONFORM TO POST OFFICE REGULATIONS
(Copies are available from the Post Office)
Urgent Samples
Cases treated as urgent are all new borns, cordocentesis specimens, pregnant couples including follow up of prenatal diagnosis, children awaiting surgery and others cases as discussed with the laboratory.
Reporting of Results
• Urgent cases. Usually within 5-7 days which is within the national guidelines. An aneuploidy screen can often be done overnight as a Fluorescent in situ Hybridisation (FISH) test (please contact the laboratory).
• Other cases. We attempt to report within the national guidelines which are within 28 days. If results are required earlier please contact the lab.
• Complex abnormalities, or abnormalities that are difficult to interpret, may require FISH to resolve the karyotype, this may delay some results.
• Results are sent to the referring clinician. Complex abnormal results are usually telephoned prior to the written report being sent and the interpretation and implication discussed. Abnormal results from urgent cases will be telephoned to the referring clinician.
• In response to telephone enquiries, only normal results or those which confirm a previous finding are given to a clinicians’ secretary or the clinic sister. All other results are only given to clinicians.
Last updated 16/10/06