By Nick Triggle Health reporter, BBC News Please turn on JavaScript. Media requires JavaScript to play. Advertisement A trained phlebotomist at St George's Hospital, London, collects cord blood Parents, hospitals and private firms are being warned over risky and illegal collections of umbilical cord blood.The Human Tissue Authority said if proper guidelines were not followed samples may be contaminated and safety compromised on maternity wards. The regulator has received reports of untrained and unlicensed people taking the blood - with one sample even obtained in a hospital car park. The blood is sought because of its potential role in combating disease. It is a rich source of stem cells, which are used to help treat diseases such as leukaemia. CORD BLOOD COLLECTION Samples can be collected while the placenta is still inside the mother or after it has been delivered The umbilical cord is clamped and a tube inserted into it to drain away the blood The sample is then put into cold storage and can be saved for years More than 15,000 samples were taken last year, three quarters by private firms who charged parents a fee of up to £2,000 The therapeutic properties of cord blood first emerged in 1988 Since then more than 8,000 cord blood transplants have been performed worldwide, mostly to treat leukaemia But some believe the potential of stem cells goes much further.[Read more...]