PRE-RELEASE QUALITY/POTENCY EVALUATION OF 1241 CORD BLOOD UNITS (CBU) BY SEGMENT TESTING: CB BANKS NEED TO INTERPRET THE SEGMENT RESULTS AND PROVIDE RECOMMENDATIONS TO TRANSPLANT CENTERS (TC).

Background & Aim To evaluate the impact of cryopreservation and storage on CBU quality/potency, segment evaluation is performed prior to release for transplant. Although FACT provides broad guidelines, interpretation of CBU segment results remains a challenge for TC. Our aim was to evaluate the NCBP segment tests and review algorithm, so we can provide clear recommendations to TC. Methods, Results & Conclusion Segment is the integral tubing of the freezing bag that contains a small amount of product. NCBP CBU processed with the AXP system have 3 segments: routinely, the first is used for identity testing by HLA typing and the second for quality/potency analysis. Potency can also be evaluated on the first segment. We compared CBU pre-cryopreservation potency values to second segment results for 1633 segments of 1241 CBU provided for transplant (period 01/2009-10/2018). Of those, 168 CBU had also first segment tested. Segment viability (viab) results (Table 1) and recovery of CD34+ cells and CFU (Table 2) allow us to set ”acceptable ranges”: results outside these ranges need to be repeated, or TC has to be notified. Potency indicators varied slightly between first and second segment; both correlated strongly with pre-cryopreservation results (Table 3). FACT pre-release specifications (Tables 1 and 2) were met in all 1633 segments except 4 (0.2%) which had lower CD34+ viab; of those, 3 were from CBU stored in two bags and the second bag's segment had CD34+ viab >95%, indicating technical problems with the first sample; for the fourth, no additional sample was available for re-testing. Our Report now indicates “CBU identity is confirmed and quality/potency indicators are satisfactory.” Segment testing requires expertise in handling and result evaluation. Pre-release segment evaluation of a representative number of CBU (3% of the NCBP Search Inventory) shows high CD34+ viab and consistently high recovery of CD34+ cells and CFU. Further, segment results correlate strongly with pre-cryopreservation values. The analysis shows that bank processes are under control and laboratory results are reproducible, for HPC, CB to be used in transplant and expansion studies. CB banks need to develop acceptable ranges for segment results based on their own data, beyond FACT guidelines, to support product release or further evaluation. CB banks need to interpret their segment results and provide guidance to TC on the quality of the products.