Cord Blood Storage – An Overview Of Cord Blood Banking Process

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After cord blood collection, the blood is saved in bags or vials; it is taken to the cord blood bank through courier service. Once it reaches the bank, the sample is rendered a unique identification number. After that, the doctors separate the stem cells from the blood and store them cryogenically (by freezing them in liquid nitrogen). After that, when needed, the cord blood stem cells are unfrozen and utilized in either Allogeneic Procedures or Autologous Procedures.


During cord blood storage, each vial is labeled with cord blood number, name of the baby, date of birth, date of processing, and the contents. Then, it enters the first stage of cryopreservation. The vials are positioned in two cryo-tanks having different temperatures and then are submerged into tanks containing liquid nitrogen. This step ensures the safety of stem cells. The series of falling temperatures prevents the stem cells from undergoing a shock due to the intense negative temperature of – 32 degrees Fahrenheit.

Freezing The Cord Blood – Liquid Nitrogen

To prevent ice crystals from forming over the stem cells, it is important to freeze the cells gradually. For this, a particular controlled-rate freezer is used. The handling processes and the freezers are designed to prevent “Transient Warming Events (TWEs). If there is a fluctuation in temperature, the cells will suffer an irreparable damage.

While freezing living tissues, they are dipped in a solvent that safeguards the cells against ice crystal formation. Ice crystals can break the cell membranes. The most common solvent used for cryopreservation is DiMethylSulOxide (DMSO), generally in a 10 percent solution. It serves as a shield around the cells.

Before placing the cells in liquid nitrogen tanks at a temperature of -196 degrees Celsius, the cells are exposed to a gradual freezing process in a vapor tank, which contains liquid nitrogen up to 25 inches to make sure the temperature stays at the above mentioned temperature . All the equipment is placed in a highly supervised and secured facility.

Types Of Freezers

Some of the public cord blood banks with heavy budgets make use of “BioArchive” freezers. They are liquid nitrogen freezers using a proprietary, robotic system controlled by a computer for cryopreservation and store a maximum of 3,626 bag units. The location as well as the retrieval of each unit is computerized.

The purpose of robotic arm is to prevent “Transient Warming Events (TWEs), when the blood samples are kept or removed from the freezer. A majority of the public cord blood banks in America are making use of “dewars”. They are insulated tanks with lids. The chief disadvantage of these tanks is that the lid has to be lifted open every time you add or remove the samples. The temperatures are under constant evaluation and quite effective for prolonged storage.

Contents Of Freezer

The cord blood is stored in either vials or bags. When the freezer racks get loaded with cord blood containers, they should be positioned at an equal distance from each other to ensure the stability of temperature. The freezer has racks to hold both bags and vials, but it is not advisable to mix the containers in one freezer. Therefore, most of the banks concentrate on one kind of container. The cold nitrogen maintains the cryogenic temperature. Some cord blood banks prefer liquid nitrogen while others prefer cold nitrogen vapor.

There are certain pros and cons of both types of nitrogen.

Pros And Cons Of Liquid Nitrogen

  • Uses a greater amount of nitrogen
  • Keeps constant temperature
  • There is a documented chance of a contagious disease leaking from a bag and infecting the recipient.
  • Its long-term viability is determined.
  • Pros And Cons Of Vapor Nitrogen

  • This is cheaper
  • There is a possibility of Transient Warming Events
  • It is safer for Quarantine tank
  • Its long-term viability is not yet determined
  • As per theory, the stem cells should remain viable forever. However, the research on cord blood has only started since the 1970s; therefore, the maximum storage time and potential usage of the cells is yet to be determined. However, cord blood stem cells, which have been saved for 14 years, have been successfully used in transplants. Therefore, we can say that the stem cells have a good shelf life and can be safely used after many years for cord blood transplant, if stored properly. It is always better to be well informed about cord blood banking before going for it.

    Source by Apurva Jain

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