Parents who bank their baby's cord blood are already thinking ahead, and many want to make sure they are investing in a product with a long shelf life. How long can cord blood be stored is toward the top of our list of frequently asked cord blood questions. As cord blood banking is 27 years young, data on the use of cord blood in transfusions are limited, but from what research on thawed cord blood units has shown, the length of cryopreservation does not affect the quality and viability of a cord blood collection.
Frozen cord blood unit in two-chamber bag
There are a few major studies from where we can draw this conclusion. Let's dig in:
Cord Blood Stored up to 11 Years
The aim of this first study was to evaluate the effect of long-term cryopreservation on the quality of cord blood units (CBUs) and the patient's recovery after cord blood transplantation. The study retrospectively analyzed the 127 adult patients with blood-related malignancies following single-unit cord blood transplantations from April 2007 to September 2014. It also looked at the quality of 95 cord blood units prior to transplantation. It is unclear to what degree the two groups overlapped.
- Of the 127 cord blood units used for transplants, 42 units were cryopreserved for long periods (5 years–11.8 years).
- Of the 95 cord blood units analyzed, 50 were cryopreserved for fewer than five years and 45 were cryopreserved for more than five years.
The study measured the recovery rate of total nucleated cells (TNCs) and CD34+ cells after thawing and engraftment in the 95 units. It found that the length of cryopreservation did not affect the number of TNCs (immune system cells) and CD34+ (stem) cells pre-freezing to post-thawing. It also found the time to patient recovery, measured by neutrophil engraftment, in the group of 127 transplantations was not affected by the length of storage.
Cord blood Stored up to 16 Years
According to the New York Blood Center, one of the first public cord blood banks, it has stored cord blood since 1993. Of the 25 years of available data, it has tested the quality of cord blood units that were frozen up to 16 years and used cord blood units in transplantation that were frozen up to 13 years. From those two sources of data, it has found no reason to believe there is any significant deterioration of cord blood during cryopreservation.
Cord blood Stored up to 23.5 Years
Dr. Hal Broxmeyer, from the New York Blood Center, has a re-occurring study on the length of cord blood cryopreservation. In 2003, he showed that 15 years of cryopreservation had no significant impact on the viability. He followed that up in 2011, with data that the quality of cord blood stored 21 years–23.5 years was not affected by the length of storage. He also promises to return with data on cord blood stored up to 30 years.
These studies provide confirmative information that the length of cryopreservation has had little impact on the recovery of viable cells and engraftment ability and show that umbilical cord blood is in no way significantly affected by the length of cryopreservation.