Abstract 17 Umbilical Cord Blood Collection. How Do Different Factors Affect CD45 Cell Viability in Our Experience?

INTRODUCTION: Umbilical cord blood (UCB) is an important source of hematopoietic stem cells for transplantation in some hematological diseases. One of the main factors influencing sample quality and transplantation success, in addition to histocompatibility, is the number of viable CD34+ cells. Over the years, different factors that could directly affect viability have been studied and evaluated. It is important to be able to define favorable ranges for obtaining high viabilities and optimal samples for their use. OBJECTIVES: The aim of our study is to evaluate the incidence of three factors temperature during transport, volume and time between collection and process of UCB over cellular viability previous to cryopreservation. METHODS: We analyzed 10483 UCB samples collected between 2018 and 2022. Cell viability values were analyzed in total CD45 using flow cytometry with 7-AAD and Annexin V. We evaluated the relationship between cell viability with the three factors mentioned above. RESULTS: We observed a tendency for viability to decrease as the blood volume collected decreases, and as the temperature and elapsed hours increase. In concordance, we found that viability is dependent on the 3 factors analyzed (p <<0.001), observing that its variability can be explained in 4% by the variation of elapsed hours as well as the collection volume, while temperature explains this variation in 1%. DISCUSSION: With our samples we can assume that the variations in the ranges analyzed would not affect them to a great extent, since they are not determinant for obtaining an average viability lower than that established as acceptable in our bank (75%). On the other hand, we also conclude that viability cannot be explained from the variation of a single factor, so it would be important to analyze the interactions between them. For the time being, and in order to improve the quality of the samples, we consider it necessary to emphasize the collection of a good volume of blood and the rapid transport of the samples for processing.