North Carolina 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 North Carolina bill was enacted 8 June 2009 and became effective 8 June 2009.
- What questions should parents ask a Family Bank about Laboratory Standards?
- Is the cord blood laboratory accredited by an agency that has specific standards for cord blood banks and conducts inspections? (ex: AABB, FACT, ISO)
- Some US states license cord blood banks (CA, MD, NJ, NY): Do they operate in those states? Note that the California Biologics License is based on AABB accreditation, but lags behind the latest AABB updates.
- Does the lab process cord blood around the clock, or only on selected shifts?
- What tests does the lab perform on maternal blood?
- What tests does the lab perform for infectious disease markers?
- What tests does the lab perform for contamination?
- Does the lab ever reject cord blood collections on the basis of the tests of maternal blood, infectious diseases, or contamination?
- Does the lab maintain a "quarantine tank" for the storage of blood that might be able to transmit an infection?
- What tests does the lab perform to measure the stem cell count of the processed cord blood and the stem cell viability?
- Does the lab/bank inform parents, prior to storage, if the collection is too small for a transplant, and give them the option not to save it?
- Does the lab/bank offer parents a refund if the cord blood collection has certain problems (contamination, low volume)? These refunds are typically only offered if the bank performed the collection as part of their service.
- What information will parents receive in the final report about their stored cord blood?
- 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 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.