Cord blood processing method
As one of the world’s largest family cord blood banks, Future Health Biobank has trialled many of the leading cord blood processing technologies over the last 20 years.
As over 100,000 families entrust their stem cell samples with us, we think it’s important you to understand the process every cord blood sample goes through to successful cryopreservation and storage. It’s down to our industry-approved processing method to ensure that each sample achieves the highest possible cell count.
Here we explain the processing method of every cord blood sample at Future Health Biobank and how it prepares your sample for storage.
What does my cord blood sample contain?
Future Health’s superior processing method means that even small amounts of blood can be processed. This can be collected by a professional phlebotomist – arranged by us – alongside delayed cord clamping, after your baby’s birth. Within this sample are:
Red Blood Cells
Composition: 40 – 45 %
Value: No value; does not contribute to the stem cell population
Composition: 5 – 10 %
Value: High value; contains key stem cell population used for treatment
Composition: 50 – 55 %
Value: Limited value; does not contribute to the stem cell population
As you can see, only 5 – 10% of the overall blood sample collected is of any value. This is where our cord blood processing method comes into play to gain the highest stem cell yield.
Volume-reduced cord blood processing
The primary, industry-approved cord blood processing method used at Future Health Biobank is volume-reduced processing. We apply this method to every cord blood sample to pass through our laboratory for maximum sample safety.
Simply put, the volume-reduced process involves reducing the size of the sample by removing the unwanted portion (Plasma and RBCs – roughly 90% of the sample), then isolating and protecting the valuable stem cells in storage. Don’t be confused if you hear about Sepax, MacoPress or AXP, these are simply machine types that all perform the volume reduction process.
There are two methods currently accepted in order to volume-reduce a cord blood sample, these are:
Centrifugal volume-reduction – the most popular method. The sample is spun at high speed in a centrifuge. This separates the blood into its constituent parts (Red blood cells, buffy coat and plasma). The unwanted portions of the blood can them be removed.
Sedimental volume-reduction – using chemicals to separate potentially toxic waste products from a sample
Why remove cord blood waste products?
‘Waste products’ refer to red blood cells within a cord blood sample. They don’t cope well in storage and can rupture releasing a toxin into the sample. This can kill off valuable stem cells, meaning higher cell loss as well as being toxic for the recipient in transplant.
1. Avoid harmful or even fatal side effects
Red blood cells have been associated with harmful or fatal side effects if too many of them are used in treatment. For this reason, the volume-reduced processing method is applied to remove the majority of red blood cells before the cord blood sample is cryopreserved and stored.
2. Safer storage
Volume-reduction has also been found to offer better cell protection during storage, resulting in higher eventual cell count and more treatment opportunities for the family
3. Optimal freezing conditions
The smaller the volume, the more uniformly the sample will freeze. This is critical to minimise cell death during freezing as well as thawing if the sample was required for transfusion.
4. Less cryoprotectant is required
Cryoprotectant is added to every sample regardless of the processing method, to stabilise and protect the sample while it is frozen down to -180°C. Unfortunately, cryoprotectant is toxic to transplant recipients in large volumes. However, significantly less cryoprotectant is needed for storage of a volume-reduced cord blood sample due to the smaller final sample size.
Whole blood processing
Although whole blood is technically an alternative processing method, it is used minimally and is generally seen as outdated. is Whole blood processing means the sample is simply prepared for storage, none of the harmful waste product is removed and the sample is generally stored in one large bag.
While storing cord blood using this method is cheaper due to lack of processing, the remaining waste products could harm the quality of the stem cell count. Very few companies worldwide provide this service, as volume-reduced is the superior method.
What do the experts say?
Don’t just take our word for it! Below you will find some extracts from independent organisations with regards to processing cord blood.
“The cord blood unit is processed by removing the red blood cells and plasma. This reduces the volume of the cord blood unit to 20ml, leaving us with all the vital blood stem cells required for transplantation. A cryopreservative (DMSO) is added to protect the blood stem cells while they are frozen. The cord blood unit is then frozen and stored in liquid nitrogen containers which are specifically designed for cord blood units.”
NHS Public Bank (Ref link: https://www.nhsbt.nhs.uk/cord-blood-bank/how-is-it-used/)
“Today most cord blood banks, both public and private, process cord blood to remove both the plasma and the red cells, and cryo-preserve the remaining “buffy coat” that holds both white blood cells and stem cells. Many doctors consider it important to remove red blood cells before preserving cord blood stem cells, and we have a fact sheet on red blood cell depletion. The reason to remove the red blood cells is because they tend to burst during freezing, which releases iron from haemoglobin that can be toxic. The alternate to removing the red cells before freezing is to wash any broken cells out of the cord blood unit upon thaw.”
Parent’s Guide to Cord Blood (Ref link: https://parentsguidecordblood.org/sites/default/files/uploaded-files/rbc-depletion-factsheet.pdf)
“In summary, given the problems with handling cord blood units that hold red cells, both in the laboratory and in the patient care setting, the current industry standard is for most cord blood banks to perform partial depletion of RBC and removal of plasma before cryopreservation. In addition, those public cord blood banks that have been licensed by the FDA all use a system to deplete RBCs and plasma.”
Andromachi Scaradavou, Medical Director of the New York Blood Center’s National Cord Blood Program