Viability and function of 8-day-stored apheresis platelets

Methods of bacterial detection and pathogen inactivation of platelets (PLTs) may allow extended storage of PLTs as long as PLT quality is maintained.

Twenty normal volunteers had their PLTs collected with an apheresis machine (Haemonetics Corp.). A variety of in vitro PLT function and metabolic assays were performed both on Day 0 and after 8 days of storage. On Day 8, a small blood sample was drawn from each donor to obtain fresh PLTs. The fresh and stored autologous PLTs were labeled with either (51)Cr or (111)In, and the radiolabeled PLTs were transfused. Posttransfusion serial blood samples were drawn to determine the relative posttransfusion recoveries and survivals of the fresh versus the stored PLTs.

Although the in vitro assays showed some differences between the two trial sites, the results were generally within the ranges expected for fresh and stored PLTs. Overall, PLT recoveries averaged 66 +/- 16 percent versus 53 +/- 20 percent and survivals averaged 8.5 +/- 1.6 days versus 5.6 +/- 1.6 days, respectively, for fresh compared to 8-day-stored PLTs. There were no significant differences in the in vivo PLT data between the trial sites or based on the radiolabel used for the measurements.

After 8 days of storage, the in vivo posttransfusion recovery and survival of autologous Haemonetics apheresis PLTs meet the proposed standards for poststorage PLT quality.