Storage of apheresis platelet concentrates after manual replacement of >95% of plasma with PAS 5

Background and objectives: Recently, a glucose- and bicarbonate-containing additive solution termed PAS 5 demonstrated acceptable 7-day platelet storage after >95% plasma replacement with PAS on the day of collection (Day 0). In this study, we examined platelet storage in >95% PAS 5 after manual washing of Day 1 apheresis platelets in plasma collected using either the Amicus or Trima plateletpheresis devices.

Material and methods: Triple platelet donations in plasma were obtained from Amicus (n = 10) and Trima (n = 10) plateletpheresis devices and stored overnight before being centrifuged and manually processed into three units with the following storage media: 100% plasma, >95% PAS 5 or 65% PAS 5/35% plasma. Platelet units were sampled on Days 1, 5 and 7 of storage using a range of tests recommended by the UK guidelines.

Results: The majority of in vitro assay results for platelets in PAS 5 were similar to results in paired 100% plasma platelets (controls). The pH of PAS 5 stored platelet units was above the UK recommended guidelines of 7·4 by Day 5. PAS 5 platelets were no more activated than controls as evidenced by comparable soluble P-selectin levels and CD62p and CD42b expression. PAS 5 platelets also exhibited adhesion and aggregation profiles higher than (Day 1) or comparable to (Days 5 and 7) controls as measured by Impact R.

Conclusion: The 7-day in vitro storage parameters investigated were comparable between >95% PAS 5 and 100% plasma platelets derived from both Amicus and Trima plateletpheresis devices, with the exception that lactose dehydrogenase release rate and pH were significantly higher in PAS 5 units.