Storage - Cryopreservation | Public Cord Blood Bank

When the collection of the cord blood in the hospital is completed, the unit is saved and sent to the lab in a cooler which maintains the temperature between 20-23⁰C. 

The collected blood must arrive at the lab within 24 hours past collection.  At the lab, the blood is weighed and a blood count is taken.  Only units which pass the minimum threshold of a billion (1X10⁹) granulated cells total are processed and frozen.

Units are processed in a closed sterile –processing bags system, which is connected to the collection bag, all the while carefully preserving appropriate sterile conditions.  All steps are performed within a biological laminar flow hood which maintains maximum sterility.  The processing of the cord blood is initiated by the addition of a specific solution that will facilitate the sedimentation and removal of most of the red blood cells by centrifugation. We use also an alternative technique to this procedure using a semi automated machine – SEPAX that functions continuously to separate the blood components automatically.

At the end of this process the separated blood cells that contains primarily white blood cells including the stem cells is suspended in the blood plasma in a volume of 20 ml and are transferred to a special freezing bag that is divided into two chambers. This chambers division may in the future, as the technology is developed, allow the use of  a portion of the unit to grow the stem cells in cell cultures in a lab in the aim to achieve higher yields of stem cells for the patient's transplantation. Before freezing, 5 ml DMSO, a preserving agent which prevents the formation of nuclei of ice that will burst and destroy the cells, is injected by an electronic pump.

The unit is then placed in a coded metal cassette which will ensure its immediate identification when needed. The freezing procedure is a slow, controlled process which takes several hours.  The freezer where the units are finally placed functions by liquid nitrogen, freezes the cord blood eventually to a temperature of -196⁰C.  It is stored at this temperature until needed for transplantation.

Prior to the cord blood processing, several samples are withdrawn for different tests to ensure its sterility, safety and viability for future transplantation.  The tests are:

• Total Nucleated blood cell count, and differential blood count.
• Microbiological cultures – to check for microbial sterility of the cord blood.
• Stem cells content that is measured by the specific protein - CD34.
• White cells viability.
• Virology – the presence of certain dangerous viruses including: HBV, HCV, HIV, HTLV, Syphilis.
• Tissue typing – HLA antigens of the unit.
• Additional samples are saved for future possible testing if required by the transplantation center or if new information regarding the child that donated the unit is obtained.

The routine tests are performed mostly in specific laboratories at Sharei Zedek and Hadassah hospitals all of which have appropriate professional and quality accreditations After all test results are received, the processing, freezing and documenting procedures are completed, and all the verifying medical and permission forms are assembled.  At that stage details of the specific blood unit are forwarded to the international registry. In this center, they are available for search to all transplant centers around the world. You may further read details of the search process in the international registry in the designated section at this website.