In vitro comparison of platelet storage in plasma and in four platelet additive solutions, and the effect of pathogen reduction: a proposal for an in vitro rating system

Background The introduction of platelet (PLT) additive solutions (PASs) and pathogen reduction (PR) technologies possibly allow extension of PLT shelf life. It was our aim to compare in vitro quality of leucocyte-reduced PLT concentrates (PCs) stored in various PASs, including PR, with those in plasma during 8 days of storage. The study was performed in four blood centres where each tested four conditions. Study Design and Methods In paired experiments (n = 12), buffy coat pools were made to which various storage media were added. Plasma served as reference; two centres used InterSol followed by PR (InterSol+PR) and InterSol without PR; T-sol, SSP+ and Composol were also studied. Results All PCs fulfilled release criteria (pH(37 degrees C) > 6 center dot 6; swirl present) until Day 8. Marked differences were seen for other parameters, including CD62P expression: 28 +/- 5; 31 +/- 7; and 39 +/- 9% for T-sol, Intersol+PR and without PR, respectively, which were higher as found for Composol (12 +/- 3%), SSP+ (15 +/- 5%) and plasma (15 +/- 6%). Three parameters (CD62P, Annexin A5, and lactate concentration) were collapsed into one rating value (6 = good quality, 0 = poor quality); PLTs in plasma had a rating of 2 center dot 8 +/- 1 center dot 0, which was higher as for T-Sol (1 center dot 5 +/- 0 center dot 5), InterSol+PR (1 center dot 3 +/- 0 center dot 6) and without PR (1 center dot 7 +/- 0 center dot 5). PLTs in potassium- and magnesium-containing PASs showed higher ratings as plasma, 4 center dot 3 +/- 0 center dot 5 for Composol and 3 center dot 8 +/- 0 center dot 8 for SSP+. Conclusion PLT concentrates in plasma, SSP+ and Composol scored better using an arbitrary rating system as PLTs stored in T-Sol or InterSol; PR further impaired rating parameters. The applicability of these differences in rating for clinical effects needs a clinical study.