In vitro storage characteristics of neonatal platelet concentrates after addition of 20% PAS-E

An observed decline in end-of-storage pH in plateletpheresis-derived platelet concentrates for neonatal use suspended in 100% autologous plasma was expected to be reversed by the addition of a platelet additive solution, (PAS)-E, increasing unit volume by approximately 20%. This study determined the impact on other in vitro storage parameters to ensure the expected increase in pH did not mask an adverse impact on component quality.

For each replicate, one of a pair from a double adult dose plateletpheresis collection had approximately 50 ml of PAS-E added on Day 3 of storage. Its unmodified twin served as a control. Each adult dose was split into four neonatal storage packs and tested on Days 3, 6, 7 and 8. Three of 12 replicates were from donors with a history of low pH at end of storage and reflected the worst-case scenario for the new components. A further experiment evaluated whether any differences were simply due to the increased unit volume.

In the nine randomly selected collections, pH on Day 8 was approximately 0.4 units higher in the test units. Platelet activation tended to be lower, with CD62P surface expression on Day 8 of 54.6 ± 9.9% compared to 65.8 ± 10.7% for controls (p < 0.001). Test units from donors with historically low pH retained pH_22°C levels above 6.8 compared to controls (<6.4 on Day 8).

The addition of 20% PAS-E by volume increased the buffering capacity of the units whilst maintaining other in vitro storage characteristics.