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In this column, we will present basic but useful information to all those interested in saving umbilical cord blood from their children or those who are interested in such stored blood for transplant purposes. Previous columns are available in our archive.

Why is there a cost?

The process of freezing umbilical cord blood and testing it is rather complex and requires a great deal of skill developed over a number of years. It is not as simple as taking food that's on a table and putting it in a freezer.

As we all know, water tends to expand or get bigger when it is frozen. Most people have done this test by taking a can of soda pop and putting it in a freezer and then forgetting that it is there. When they come back a couple of days later, the can has exploded. It has exploded because water takes up more space when it is frozen than in a liquid phase. They also know this when it snows. About 10 inches of snow only equals about one inch of water. Thus water takes up a larger space when it is frozen. As a result, when cells are frozen, they will expand or get bigger and the cell lining or membrane may actually rupture and the cell will die in the freezing process. Thus, when freezing human cells, the cells have to be protected from freezing too quickly and rupturing the lining around the cells. There are chemicals called cryo-protectants which are added to the cells to keep them from freezing too quickly and to keep the cells from expanding too greatly in the freezing process. The freezing process is closely monitored to make sure that the cells are frozen in a slow and steady way so that there are no water crystals that form within the cells and kill the cells. All of the technologists who are involved in the cryopreservation or freezing process have studied this for some time and practiced it. Thus, the fact that we require very skilled technicians in order to complete this process increases the cost.

In addition, the cells are then placed in liquid nitrogen. Nitrogen is the most common element in the air we breathe – it is about 80%. At room temperature, nitrogen is in a gas phase but in a liquid phase, it is very cold. It is colder than -320 degrees Fahrenheit. This is a very good temperature to preserve cells because we think they will last the longest when frozen as cold as we can get them. These special freezers require very close monitoring to make sure that they are functioning adequately to protect the lifesaving cells within them. As a result, this increases the cost.

As those of you know who have been reading this column, Cryo-Cell splits the samples to be frozen so that they are cryopreserved in two separate states thereby adding a security protection to the specimens which have been saved.

Viability Testing of Cord Blood

There are a number of tests which are performed on the mother's blood and the collected umbilical cord blood cells. The most important tests have to do with looking for maternal infections and also having to do with the number of cells present which could be used for transplant purposes at a later time.

It is a federal requirement that all blood products be tested for the usual viruses that can be transmitted from person to person such as the viruses that cause various types of hepatitis and the viruses that cause AIDS. There is a long list and this list keeps growing. It is important to do the testing for such viruses on the mother's blood to ensure that the cord blood is free from any infectious material.

There are particular cells that have certain cell membrane or lining characteristics which distinguish them from the other cells and tell us that these are the cells that have the capability of growing well in another person and repopulating their entire blood forming and immune system. These cells are CD34+, a marker which can be tested for in the laboratory. Thus, the specimen of cord blood that is initially cryopreserved is tested for the total number of cells present and then the number of CD34+ cells, representing a sub-fraction or small component of the overall cell number but the very important cells that have to do with growth in another person. These are the cells that the technologists want to survive long-term because these are the cells that have the capability of growing once again and forming all the components of blood that circulate, such as white cells having to do with fighting infections, red cells having to do with carrying oxygen, and platelets having to do with clotting. Once these data are collected, they are then stored in a computer in the file for that particular specimen which has been saved.

Sometimes, individuals will want to know whether or not the sample has been sexed or whether or not tissue typing has been done. Because these tests are very costly, they add a significant amount of cost to the cord blood specimen and thus are not routinely done. However, small samples of the cord blood which have been saved are kept in very little vials or containers so that these samples can be sent for tissue typing or sexing if that becomes necessary. Usually, the sex of the baby from which the sample has been saved is noted in the record so that sexing of the cells does not have to be done in a laboratory.

Cryo-Cell, with headquarters in Clearwater Florida, is the most established of the private cord blood banks in the United States. Specimens collected in delivery rooms are split and stored for safety purposes both in Florida and Arizona. Cryo-Cell is the only publicly traded stem cell bank and thus is regulated by the Securities and Exchange Commission in addition to the usual laboratory and medical regulations. Cryo-Cell nurse staff are available 24/7 to address your questions and queries and to facilitate the collection, freezing and long term storage of umbilical cord blood specimens.

by Michael E. Trigg, M.D.
Former Chair, Medical & Scientific Advisory Board of Cryo-Cell International, Inc.

Future areas of discussion:

In the next column, we will discuss how the stem cells are monitored for viability for long periods of storage, how the stem cells are often used for leukemia treatment, and why the size of the sample collected may vary in usefulness for treatment.

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