The blood from an infant's umbilical cord and placenta is rich in stem cells, which are cells that have the ability to renew themselves and transform into other types of cells. Collecting your child's cord blood at the time of delivery provides an insurance policy of sorts because this blood can be used later for the child, a parent or sibling to treat a variety of diseases and conditions. Cord blood is stored at a cord-blood bank, where strict procedures must be followed to ensure the integrity of the cord blood cells for later use.
Sample Processing
Once a cord blood sample has been collected, it must be processed within 48 hours. The blood is therefore transported by courier to the laboratory where technicians reduce the total volume collected by removing red blood cells and plasma, the liquid portion of blood, leaving only the stem cells for storage. The sample is analyzed to determine the concentration of stem cells present and a report is prepared to document this information for later use.
A special chemical, called a cryopreservative, is added to the sample to aid in the freezing process. The sample is slowly frozen, at a rate of 1 degree C per minute until it reaches the optimum freezing temperature and then transferred to storage.
Temperature
Cord blood is stored either in the liquid phase of liquid nitrogen or the vapor phase of liquid nitrogen. The traditional method is in the liquid phase, at a temperature of -190 degrees C. Recent questions have arisen as to whether any infections or contamination can travel through the liquid phase from one sample to another.
Vapor phase storage, at a temperature of -130 degree C, historically was less reliable because maintaining constant temperature in the vapor phase was difficult. New storage tanks, however, are now able to maintain a constant temperature, so many cord-blood facilities are transferring to vapor phase storage.
Identification
Successfully storing a sample is important, but just as important is ensuring each sample is clearly labeled and can be found. Most cord-blood banks utilize a bar code system with a unique identifier on the sample and all paperwork. Each client is also assigned a unique number that is included on the sample and paperwork. The exact location of each sample within the storage facility is recorded and kept in a computer database.
Safety Precautions
To ensure the safety of all cord blood samples, the mother must provide samples of her blood. These samples are tested to determine the presence of any diseases that might have been passed along to the infant. If there is any disease present the blood will be stored in a separate area away from any non-disease blood to be sure there is no cross-contamination.
Storing your child's cord blood is worth it only if the stem cells are viable for use if needed. To ensure all samples are kept frozen at optimal temperatures, cord-blood banks accredited by the American Association of Blood Banks have a number of safety features including continual electronic monitoring and multiple alarm systems to notify personnel of any temperature changes.
