Virginia was the first state to pass legislation where the bill itself explicitly endorses the use of educational materials from Parent's Guide to Cord Blood Foundation. Virginia 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 Virginia bill was enacted 9 Mar. 2010 and became effective 1 July 2010.
- What are TNC, MNC, CD34+, and CFU, and why should I care?
These are all ways of counting cell types, and they tell you whether or not your cord blood collection has lots of stem cells and if they are healthy.
Stem cells happen to be Mono-Nuclear Cells or MNC: when you look at them under a microscope there is only one nucleus. Unfortunately, one of the most difficult aspects of stem cell biology is that you can't identify a stem cell just by looking at it. There are other types of blood cells which are also MNC, such as nucleated red blood cells. The only proof that a cell is a stem cell comes from how it behaves when it multiplies.
Scientists have worked for years to develop various chemical stains which have a high affinity for stem cells. The best known marker for blood-forming stem cells is that they test positive for CD34, a protein found on the surface of stem cells. But, CD34+ counts are not an accurate measure of stem cells: CD34+ results vary between labs, they can vary within a single lab, and only 1-2% of the MNC that have CD34+ are actually stem cells.
The Total Nucleated Cell count or TNC is the test most often reported as a measure of the cell count after cord blood processing. The main advantage of measuring TNC is that the count is highly reproducible within and among labs, so it can be used accurately throughout the blood banking community. Even better, the TNC count can be automated with the use of a device called a flow cytometer.
At present Colony Forming Units or CFU are considered to be the best measure of whether stem cells are "viable", or quite frankly alive. The TNC count includes both living and dead cells. In the CFU test a small portion is watched under controlled conditions to see if stem cells divide and form colonies. This used to be a subjective measure, but recently it has been standardized with technology to image the cells and count colonies in the image. The only remaining problem with the test is that it takes days for colonies to grow.
- 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
- Once we have stored cord blood for our family, how long should we keep it?
- Indefinitely. From an economic perspective, it does not make sense to invest in the up-front processing fee and pay for years of annual storage, and then throw out the investment. That would be like buying life insurance and then cancelling it because you have not died yet. Especially given that the probability of some one in the immediate family needing a transplant increases with age. Even if the cord blood collection was small, and the child becomes too large to use it for a transplant, it could still be enough cells for a regenerative medicine therapy. The science of cryobiology tells us that cells which are cryogenically preserved remain viable for decades. It has been confirmed that cord blood stem cells were still viable after being frozen 23+ years.
Broxmeyer, H.E. Cell Stem Cell 2010; 6(1):21-24
Mazur, P. Science 1970; 168(3934):939-949
Nietfeld, J.J. et al. BBMT 2008; 14:316-322