Cancer Diagnosis Program | Biorepositories and Biospecimen Research Branch

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Effect of umbilical cord blood prefreeze variables on postthaw viability.

Author(s): Pope B, Hokin B, Grant R

Publication: Transfusion, 2015, Vol. 55, Page 629-35

PubMed ID: 25332061 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to determine the effect of pre-freezing variables, time to freeze, and freezing rate on the post-thaw viability of UCB. UCB was collected from 257 women into citrate phosphate dextrose (CPD), transported by courier to the stem cell unit with temperature stabilization at 15-25°C, and processed between 5h 28 min and 54 h 3 min after collection. UCB was centrifuged at 10°C, volume reduced, and RBCs were separated out. After post-processing sampling, UCB was mixed with prechilled DMSO and autologous plasma, frozen in a control rate freezer, and stored in liquid nitrogen vapor. Specimens were thawed in a 37°C water bath.

   Summary of Findings:

   Post-thaw viability was weakly correlated with pre-freeze viability (r=0.218, p=0.001), but viability was lower post-thaw than pre-freezing. Post-thaw viability was also found to be significantly positively correlated with pre-freeze RDW (r=0.216, p=0.001), volume of plasma in freeze mix (r=0.181, p=0.004), total volume (r=0.181, p=0.004), and post-thaw percentage of CD34 recovery (r=0.358, p<0.001) and negatively correlated with pre-freeze percentage of neutrophils  (r=−0.266, p<0.001), RBC count (r=−0.319, p≤0.001), Hb (r=−0.231, p<0.001), Hct (r=−0.268, p<0.001), freezing rate (r=−0.174, p=0.007), and time to freezing (r=−0.290, p<0.001). Hct was strongly correlated with RBC count (r=0.751, p<0.001) and Hb (r=0.812, p<0.001), very weakly negatively correlated with RDW (r=−0.177, p=0.004), and thus the other RBC markers were not further studied. Together, pre-freeze neutrophil count, Hct, and viability, along with the freeze rate and time to freezing, accounted for 30% of the variability in post-thaw viability.

   Biospecimens

   • Bodily Fluid - Cord Blood

   Preservative Types

   • None (Fresh)
   • Frozen

   Diagnoses:

   • Pregnant

   Platform:

   Analyte	Technology Platform
   Cell count/volume	Flow cytometry
   Protein	Hematology/ auto analyzer
   Cell count/volume	Hematology/ auto analyzer

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Preaquisition	Biomarker level	≤41.20% neutraphils 41.21-49.35% neutraphils 49.36-55.82% neutraphils ≥55.83% neutraphils Hematocrit of ≤0.590 Hematocrit of 0.591-0.620 Hematocrit of 0.621-0.650 Hematocrit of 0.651-0.690 Hematocrit of ≥0.691
   Biospecimen Preservation	Type of fixation/preservation	Frozen None (fresh)
   Storage	Freeze/thaw cycling	0 cycles 1 cycle
   Storage	Storage duration	≤12 h 12-24 h 24-36 h >36 h
   Biospecimen Preservation	Cooling or freezing method/ rate	≤0.8°C/min 0.8-0.9°C/min >0.9°C/min

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