Platelet transfusion is a common practice in onco-hematologic patients for preventing or treating hemorrhages. Platelet concentrates can be transfused with therapeutic or prophylactic purposes. With the aim to help clinicians to take the decisions on platelet transfusion, some guidelines have been developed based on the current scientific evidence. However, there are some controversial issues and available scientific evidence is not enough to solve them. There is little information about what is the best platelet product to be transfused: random platelets or single donor apheresis platelets, and plasma-suspended or additive solution suspended platelets. Platelets are often transfused without respecting the ABO compatibility, but influence of this practice on platelet transfusion outcome is not well established. In the prophylactic platelet transfusion set there are some questions unsolved as the platelet threshold to transfuse prior to specific procedures or surgery, and even if platelet transfusion is necessary for some specific procedures as autologous hematopoietic stem cell transplantation. A challenging complication raised from multiple platelet transfusions is the platelet transfusion refractoriness. The study and management of this complication is often disappointing. In summary, although it is a widespread practice, platelet transfusion has still many controversial and unknown issues. The objective of this article is to review the current evidence on platelet transfusion practices, focusing on the controversial issues and challenges.

Background and Objectives: Umbilical cord blood (UCB) contains haematopoietic stem cells and can be used as an alternative to bone marrow transplantation in certain cases. Engraftment was dependent upon the haematopoietic progenitor cell content of the cord blood units. This study was designed to investigate the influence of obstetric, neonatal and collection factors on the volume and haematopoietic content of UCB donations. Material and Methods: A retrospective analysis of obstetric and neonatal factors was performed from 300 cord blood donations in Valencia Cord Blood Bank. Maternal, neonatal and collection factors influencing cord blood quality measured as volume, total nucleated cell count, CD34+ cells and colony-forming units (CFU) were analysed. Results: Bigger babies produced cord blood units with larger volume, higher cells counts, CFU and CD34 cell counts. In the multivariate analysis, we found that both placental weight and mode of collection were predictor variables for total nucleated cell count, CD34 cells and CFU. Conclusion: Our study concludes that cord blood units must be collected before placental delivery and that birth weight, as an estimation of the placental weight, could be added to standard cord blood donors criteria in order to improve the bank efficiency.