In vitro evaluation of prestorage pooled leukoreduced whole blood-derived platelets stored for up to 7 days.
Advantages to storing whole blood-derived platelets (PLTs) as a pool for 7 days would include operational efficiencies and facilitation of bacterial testing and pathogen inactivation. The in vitro quality of pre-storage pooled PLTs stored for up to 7 days was assessed. Leukoreduced PLTs were pooled before storage (5 units/pool) and stored for either 5 or 7 days. Samples were collected at the time of pooling and either on Day 5 (n=16-29) or on Day 7 (n=4-30) and tested for biochemical and activation markers and morphology and/or shape change. Control PLTs were stored individually for 5 or 7 days and then tested as indicated above. The mean PLT counts (x10(9)/L) were similar: control PLTs, 1344 (464 SD); and prestorage pooled PLTs, 1327 (220 SD; p=0.93). On Day 5, the pH value was significantly lower (p<or=0.0001) for the prestorage pooled PLTs. Lactate and partial pressure of O2 (pO2) were significantly higher (p<or=0.003). On Day 7 of storage, significant differences were noted with pH, pCO2, and hypotonic shock all being lower with the prestorage pooled product, whereas pO2, lactate, and morphology scores were higher (p values all <0.03). Although significant differences were found, the magnitude of the difference would not be expected to impact on transfusion outcomes. These results suggest that prestorage pooled PLTs can be stored for up to 7 days; however, studies are needed to ensure that the clinical benefit of PLTs stored as a pool is not inferior to those stored individually.