Michigan has state legislation around cord blood education that follows the Institute of Medicine guidelines and mandates/encourages physicians to educate expectant parents about ALL forms of cord blood banking. The Michigan bill was enacted 4 Jan. 2007 and becomes effective "upon determination of sufficient funds" for development of educational materials.
- Processing: How is cord blood processed before storage?
The three main components of cord blood, like any blood collection, can be separated by weight: the heaviest layer is the red blood cells (RBC), the lightest is the plasma (a clear white liquid), and in the middle is a pinkish layer called the "buffy coat" which contains the white blood cells (WBC), including stem cells. When banks process the cord blood, the final separated component that goes into storage is the buffy coat, even though only about 1% of the cells are actually stem cells. There is no procedure to separate out the stem cells alone.
The vast majority of blood processing methods rely on the different density of the three main blood components. They can be separated by sedimentation, or by centrifuge, or by a combination of the two techniques. The procedure can be performed manually by trained technicians or by automated machine.
- Processing: Must cord blood be processed before storage?
The earliest cord blood transplants were performed with whole cord blood. Thus, it is not absolutely necessary to process cord blood in order to save patient lives. There has never been a prospective randomized trial to compare transplant patient outcomes with cord blood that had been stored whole versus processed.
Most cord blood banks, both public and private, now process cord blood to remove both the plasma and the red cells, and cryo-preserve the remaining buffy coat holding stem cells. Some banks also save the removed red cells and plasma in companion storage. Some banks save a sample of maternal blood.
The removal of plasma is also called volume reduction. The volume reduction enables more collection units to fit in a freezer and requires less cryogenic nitrogen per unit.
Also, the majority of banks remove red blood cells prior to freezing, primarily because these cells often burst during freezing and release iron from hemoglobin that can be toxic. The alternate to removing the red cells before freezing is to wash any broken cells out of the collection upon thaw. Removing the red cells also removes the donor's blood type (the ABO and Rh types). When cord blood goes from a donor to a patient for a transplant, the donor and patient can be compatible on all the HLA types used for transplant matching and still have incompatible red blood types.
- What is delayed cord clamping?
Some people feel that the blood in the umbilical cord should be allowed to flow into the baby and that the cord should not be clamped while it is still pulsing. Medical studies have shown that, particularly in parts of the world with poor infant health care, delayed cord clamping can help protect the baby from anemia (low blood counts) during the first 6 months of life. However, a prolonged delay will allow the blood in the cord to clot, and the opportunity to collect the blood for stem cells will be lost. Therefore, if clamping is delayed, it should not be more than two minutes.
Hutton, EK & Hassan, ES, JAMA 2007; 297:1241-1252
van Rheenen, P et al., Tropical Med. and Internal Health 2007; 12(5):603-616
Abalos E., 2009; The World Health Organization Reproductive Health Library