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Collecting Cord Blood
When a baby is delivered by an obstetrician, the umbilical cord may be clamped and cut within seconds of birth. The phrase "delayed cord clamping" is defined as a minimum of one minute wait before clamping the umbilical cord. If the umbilical cord is still pulsating, and the baby is positioned so that blood can flow through the cord, then delayed clamping will allow the newborn to receive some of the stem cell rich blood in the umbilical cord.
Studies have shown that, in parts of the world with poor nutrition or poor infant health care, delayed cord clamping can help protect the baby from anemia (low blood counts) for up to 6 months after birth. However, the value of delayed cord clamping for full-term babies in developed nations is not proven, despite numerous studies. One study of full-term babies born in Sweden found that the group with delayed cord clamping had slightly higher social skills at age 4 years old, but that study has not been confirmed by other groups so far.
The World Health Organization (WHO) has issued an international guideline to delay cord clamping by one minute. In the United Satates, the American Congress of Obstetricians and Gynecologists (ACOG) has issued an opinion stating that evidence exists to support 30-60 second delayed cord clamping for preterm infants. However the ACOG medical review did not find sufficient evidence to support delayed cord clamping for full term infants, where the benefits of increased blood volume have to be weighed against an increased risk of newborn jaundice.
Hutton, EK & Hassan, ES, JAMA 2007; 297:1241-1252
van Rheenen, P et al., Tropical Med. and Internal Health 2007; 12(5):603-616
Andersson, O. et al. JAMA Pediatrics 2015; 169(7):631-638
WHO Guideline: Delayed umbilical cord clamping for improved maternal and infant health and nutrition outcomes. Geneva: World Health Organization; 2014.
ACOG Committee Opinion. Timing of Umbilical Cord Clamping After Birth. Number 543, December 2012. Reaffirmed 2014.
There are two methods of collection in common use. One is to hang a blood bag lower than the mother and let gravity draw blood down the tube into the bag. This method is used in most countries of the world, because it has the fewest steps, and therefore the fewest opportunities for mistakes or contamination.
The second method is to actively draw the blood out, just like when a person has a blood draw for a medical test. The draw can be done with a standard syringe or with a bulb in the bag tubing that creates suction. Studies have shown that actively drawing the blood will collect a larger volume faster.
The median size of cord blood collections in family banks is 60mL or 2 ounces. That small volume of liquid corresponds to 470 million Total Nucleated Cells (TNC) or 1.8 million cells that test positive for the stem cell marker CD34. Thus, most healthy full-term babies have over a million blood-forming stem cells in their umbilical cord blood. By comparison, most public cord blood banks will only keep collections that are much bigger than average, and throw out the donations that are below a threshold of a billion TNC, corresponding to a blood volume of about 90-100 mL or 3 ounces.
Sun, JJ et al., Transfusion Sept. 2010; 50(9):1980-1987
2. Sterilize before every needle stick. When in doubt, sterilize again!
3. Volume, volume, volume. You want to "milk the cord" for as much blood as possible. If the blood vessel you are using stops working, try another or move upstream, but sterilize first.
Donate Cord Blood
Although a few such cases have actually happened, it is very very unlikely to get your cord blood back once it is donated. If you think that donating cord blood is way of banking it for your family for free, you are making a big mistake.
When a mother signs the Informed Consent form to donate cord blood, she gives up any guaranteed access to that blood. First of all, the public bank may throw the blood out simply because it does not meet their size threshold, or simply because the paperwork is not complete. Secondly, even if the blood does make it into public storage, it may be released to some one else.
Unlike organ donors, cord blood donors do not receive any priority treatment or waived fees if your child later needs a donor. The reward for donating cord blood is the possibility that your baby may Be The Match that saves a life.
In theory, any expectant mother who passes the medical screening is eligible to donate. In practice, the biggest hurdle faced by families who wish to donate is finding a bank to accept their donation. There are only about 200 hospitals in the US that collect cord blood donations from births, and most of them require you to register for donation weeks ahead of the birth. The handful of programs that accept mail-in donations are opening this opportunity to the rest of the American public.
Find a Family Bank
- Is the enrollment fee charged once per family, or for each birth?
- Is the first year of storage included in the processing fee?
- Is the storage fee guaranteed fixed?
- Are there any coupons currently available? Most banks are constantly running a "special limited time offer".
- Are there any professional discounts? Most banks offer discounts to medical professionals and military personnel. Some banks have discounts for first responders or students. It pays to shop for these deals.
- Do parents have the option of a partial or full refund if they decide not to store the cord blood for any reason? For example, if the lab tests show contamination and the cord blood should not be saved, what happens? Full refunds are typically only offered in situations where the bank provided staff to perform the collection service.
- Should the family ever need the cord blood, check that the bank does not charge to release it.
Usually the answer is YES. However... some hospitals have signed exclusive contracts requiring their patients to use certain family banks, so it is best to check in advance.
Those hospitals who have made exclusive partnerships will argue that it improves their level of care, because their staff train with and stock the collection kits for the banks they have approved. The hospital probably has a financial incentive too. However, for parents it means a lack of consumer choice.
In some countries, national regulations hold Family Banks to the same standards as Public Banks, so an independent accreditation is not necessary (Examples: Germany, Israel). But in most countries the federal requirements for Family Banks are not as strict as Public Banks, and then a voluntary accreditation is desirable. For example, in the United States the FDA registers and inspects Family banks, but does not require them to have a BLA License like Public Banks.
Caveat: The process of registering with an accreditation agency and getting inspected can take a year, so it is understandable if a brand new lab does not have an accreditation yet.
2. Travel conditions - It is best to pick a bank that can receive and process the cord blood within 48 hours of birth. It is also best for the cord blood to be shipped in a transport container that will maintain it at close to "room temperature".
Shipping Cord Blood and Cord Tissue to the Bank
The Parent's Guide to Cord Blood Foundation recommends shipping with a courier that has a division specializing in "Life Sciences" transport. This helps to insure that your critical shipment is not misplaced, arrives promptly, and is maintained within the acceptable temperature range during transport from the hospital to the lab.
The first priority for parents to consider is the cord blood shipping time: Once the cord blood is harvested, the blood cells and stem cells gradually begin to die. Public cord blood banks set a limit of 48 hours on the time between birth and processing the blood for cryogenic storage. It would be a "best practice" if family banks also followed the 48 hour window.
The second priority for parents to consider is the cord blood shipping temperature: The standard procedure for transporting fresh cord blood is to keep it within an ambient temperature range of 15 °C (59 °F) to 25 °C (77 °F). Priority shipping services may guarantee the arrival time, but not the temperature conditions during transit. The cord blood might get too hot or too cold while sitting in the back of a truck, on a loading dock, or in the cargo hold of an airplane. A specialty courier with Life Sciences expertise will carry the cord blood in a controlled environment.
Parents can improve the survival of their child's cells during transit to the cord blood laboratory by selecting a family bank that provides a well insulated shipping container and that provides a specialty courier who maintains the shipment within the desired temperature range. In many countries it is standard practice for the shipping container to have a temperature logger.
In the United States, the post 9/11 security requirements of the Transportation Security Administration (TSA) require that specialty couriers can only offer cord blood shipping through those cord blood banks that are registered with the TSA as a "Known Shipper". Before 9/11, specialty couriers could market their services directly to consumers, and in some countries this is still possible. Parents should check if a Family Bank offers specialty courier services before they sign a contract.
Some data points:
- FACT accreditation standards require the 48 hour window for public donations but allow 72 hours for family banks.
- AABB accreditation standards do not specify a time window.
- The US FDA recommends the 48 hour window.
- The US state of NY Dept. of Health requires a 48 hour window.
Laboratory Processing of Cord Blood
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.
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.
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.
Questions Parents should ask a Family Bank
- What instructional tools are provided for the physician and delivery staff?
- Will the cord blood company actively contact the labor and delivery staff for you -- or are parents responsible for keeping them informed and coordinated?
- What collection method do they use: gravity drip or blood draw?
- Is the collection blood bag sterile, both inside and out, so that it can be used in the operating room for a C-section?
- Do they provide the option of collecting additional stem cells from the placenta or tissue of the umbilical cord?
- Is the cost of shipping included in the contract?
- Does the shipping company offer bed-side pick-up?
- On weekends, are the laboratory staff in-house or on-call?
- Does the bank guarantee to get the blood to the lab and processed within a certain time window?
- Does the shipping container have a temperature logger?
- If the bank uses a courier, does the courier have possession of the cord blood throughout transit? (ie: Does the courier sub-contract to another shipping company that is not a medical courier)?
- 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?
- What type of records do parents receive after storage?
- Does your contract state that the storage fee is fixed, or may it increase later?
- Does the bank reserve the right, in your contract, to change storage facilities?
- Does the bank operate their own storage facility, or is it provided by another laboratory?
- What type of accreditation or other certifications does the storage facility carry? In most banks the cord blood is stored in the lab where it was processed, and the accreditation of the lab covers the storage conditions.
- What is the geographic location of the storage facility: Is it at risk for hurricanes, earthquakes, or other natural disasters?
- What type of back-up systems does the storage facility have in case of power failure?
- What type of security systems does the storage facility have?
- Is the family cord blood bank a publicly-held or privately-held company?
- Is the company affiliated with a hospital or research institution?
- Is the company involved in bio-technology research and development?
- What other medical services does the company perform?
- How long has the company been banking cord blood?
- Who directs the day-to-day business of the company? Many cord blood banks have famous doctors on their Board of Directors; but they are not involved with the day-to-day operations.
- What is the lab inventory of cord blood collections, both public and private? This speaks to their staff's experience with storing cord blood.
- How many cord blood collections has the bank released from their own lab for therapy? This speaks to their staff's experience with releasing cord blood.
Stem Cell Transplants with Cord Blood
1.3 mL of cord blood for every pound of patient weight, -or-
2.9 mL of cord blood for every kg of patient weight
However, as more transplant centers are adopting the practice of giving adult patients "double cord blood transplants" with two cord blood units, it is less critical for both units to have adequate cell dose.
Reed, W et al., Blood 2003;101(1):351
Barker, JN et al., Blood 2005;105:1343-1347
Eapen, M et al. Lancet 2007;369:1947-54
Rocha & Gluckman Brit. J. Haematology 2008;147:262-274
Delaney, C et al., Brit. J. Haematology 2009;147:207-216
Michallet et al. 2010 Blood 2010;116:Abstract#361
Briefly, there are 6 HLA types that are important for stem cell transplants: in a bone marrow transplant the patient and donor must match at all 6 (100% match), whereas a cord blood transplant is just as effective at curing patients with only a 4 out of 6 match (67% match) between donor and patient. This is the reason that donations to the national cord blood inventory managed by NMDP are so important to help patients who come from minority or mixed racial backgrounds.
The HLA type of cord blood is always measured by public banks, and then the type is listed on a registry that can be searched by patients seeking a transplant. Family banks typically do not measure the HLA type at the time of banking, because it is an expensive lab test and and can always be checked later from a testing segment of the stored cells.
The two important measures of patient outcome are: long-term survival, and the impact on quality of life from graft-versus-host disease (GvHD). Sibling donors tend to trigger less GvHD. Also, sibling donors are available faster than searching for an unrelated donor, and patients have better survival when they go to transplant faster after diagnosis.
The exact comparison of outcome between sibling or unrelated donor varies with the patient diagnosis. The NMDP website has a page on this, with numerous references. For many cancers the outcomes are comparable, although sibling donors have a slight edge. The largest study was by Weisdorf et al. 2002, for over 2900 patients with CML leukemia. When correcting for all other factors, the survival with sibling donor vs unrelated donor was 68% vs. 61%. Sibling donors show a significant improvement for pediatric cord blood transplants of hereditary disorders. The European Blood and Marrow Transplantation Group (EBMT) reported 3 year survival rates of 95% from a sibling donor vs. 61% from an unrelated donor.
Weisdorf, D.J. et al. Blood 2002; 99:1971-1977.
Bizzetto, R. et al. (EBMT) Haematologica 2011; 96(01):134-141
Regenerative Medicine with Cord Blood
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
All the reasons that you banked for the first child are still valid for additional children.
1. If you want the baby to have the option of using his/her own cells, then you need to bank them.
2. If you are banking to cover siblings, then the ability to use cord blood from one child for another depends on whether they have matching HLA type. Two full siblings have a 25% chance of being a perfect match, a 50% chance of being a half match, and a 25% chance of not matching at all. For a cord blood transplant, donor and patient must match at 4 out of 6 (67%) HLA types. The more siblings with banked cord blood, the more chance that they cover each other for possible transplants or other therapies for which sibling stem cells are accepted.
Odds of sibling match are based on haplotype inheritence: that the child will receive 3 HLA types as a group from each parent.
Cord Blood Education
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