Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

Background: Cryopreserved umbilical cord blood (CB) is increasingly used as a cell source to reconstitute marrow in hematopoietic stem cell transplant patients. Delays in cryopreservation may adversely affect cell viability, thereby reducing their potential for engraftment after transplantation. Study Design and Methods: The impact of delayed cryopreservation for up to 3 days on the viability of both CD45+ and CD34+ cell populations in 28 CB donations with volumes of 58.40±15.4mL (range, 39.4-107.4mL) was investigated to establish whether precryopreservation storage time could be extended from our current time of 24 to 48 hours in line with other CB banks. Viability was assessed on 3 consecutive days, both before and after cryopreservation, by flow cytometry using 7-aminoactinomycin D (7-AAD) and annexin V methods. Results: The results using 7-AAD and annexin V indicated the viability of CD34+ cells before cryopreservation remained high (>92.33±4.11%) over 3 days, whereas the viability of CD45+ cells decreased from 86.36±4.97% to 66.24±7.78% (p<0.0001) by Day 3. Storage time significantly affected the viability of CD34+ cells after cryopreservation. Using 7-AAD, the mean CD34+ cell viability decreased by approximately 5% per extra day in storage from 84.30±6.27% on Day 1 to 79.01±7.44% (p<0.0057) on Day 2 and to 73.95±7.54% (p<0.0001) on Day 3. With annexin V staining CD34+ cell viability fell by approximately 7% per extra day in storage from 77.17±8.47% on Day 1 to 69.56±13.30% (p<0.0194) on Day 2 and to 62.89±15.22% (p<0.0002) on Day 3. Conclusion: This study demonstrates that extended precryopreservation storage adversely affects viability and should be avoided. © 2013 American Association of Blood Banks.

Original publication




Journal article



Publication Date