Samples requirements for cytogenetic and molecular cytogenetic services

Cytogenetic tests are generally carried out on cultured cells and collection and transportation requirements are important.

Sample types and referral information

Fetal blood samples should be taken into lithium heparin.

For amniotic fluid we require 10-20ml in a sterile universal container.

Chorion biopsies (minimum 5mg) should be placed in sterile heparinised culture medium. We will supply transport medium on request.

Other solid tissues should be placed in sterile culture medium. If this is not available then contact the laboratory for advice.

For array-CGH testing we required 4-8ml of venous blood in EDTA.

NOTE: Specimens should not be frozen or placed in preservative or fixative.

Please include at least 2 identifiers on the tube i.e. NAME and DATE OF BIRTH (which should be checked by the patient).

All samples should be sent with a Laboratory Request Form or Prenatal testing request form with the following information:

  • Clearly indicate the disease to be tested in the Cytogenetics analysis section of the form.
  • Include name (in full) of referring consultant and their hospital.
  • Include as much clinical information and family history as possible so as to be able to link family members together.

The Laboratory will assume that consent has been taken locally if the relevant section of the request form has not been completed.

Samples should be sent to the laboratory as soon as possible after collection and should reach us within 5 days of being taken. Prenatal samples should arrive at the laboratory before 4.00. p.m. on the day of sampling. Amniotic fluid samples sent by first class post will be accepted but it must be understood that this will result in a longer reporting time. In any case, posting over a weekend should be avoided.

Sample rejection

Please note that samples not meeting the above criteria, or that are unlabelled or not accompanied by referral paperwork may be rejected. The referring clinician will be contacted when a sample is to be rejected in order to organise a further blood sample to be taken.

Sending samples

Peripheral blood samples can usually be sent by first class post and should arrive in the laboratory on Monday, Tuesday, or Friday for optimum results. Avoid sending samples over a weekend, as they may deteriorate if they cannot be attended to.

When sending samples, please make sure that the containers are tightly capped and placed in appropriate bags, which have a separate pocket for the accompanying documentation. All samples must be clearly labelled.

Samples sent by first class post, hospital transport or courier should be packaged according to UN3373 and Post Office guidelines. Blood samples for joint molecular genetic and cytogenetic analysis can be packaged together.

The address for specimen reception is:

SW Thames Regional Genetics Laboratory,
Specimen Reception,
Jenner Wing, Lower Ground Floor,
St. George’s University of London,
Cranmer Terrace,
SW17 0RE

Please contact the laboratory on 020 8725 5332 if you have any queries about sample tubes or testing.