BACKGROUND: Platelet (PLT) storage adversely affects PLT structure and function in vitro and is associated with decreased PLT recovery and function in vivo. In pediatric transfusion medicine, it is not uncommon for small residual volumes to remain in parent units after aliquot preparation of leukoreduced apheresis-derived PLTs (LR-ADP). However, limited data exist regarding the impact of storage on residual small-volume LR-ADP.

STUDY DESIGN AND METHODS: Standard metabolic testing was performed on residual volumes of LR-ADP after aliquot removal and PLT aggregometry using a dual agonist of ADP and collagen was performed on stored, small-volume aliquots (10-80 mL) created from an in vitro model of PLT storage.

RESULTS: Seventy-seven LR-ADP underwent metabolic (n = 67) or metabolic and aggregation (n = 10) studies. All products maintained a pH value of more than 6.89 throughout storage. Lactate and pCO2 increased proportionally with longer storage time. Regardless of acceptable metabolism during storage, aggregation in 10- to 20-mL aliquots was impaired by Day 4 and aliquots less than 40 mL demonstrated the most dramatic decrease in aggregation from baseline.

CONCLUSIONS: Despite maintenance of acceptable metabolic conditions, residual volumes of LR-ADP develop impaired aggregation in vitro that may adversely affect PLT survival and function in vivo. At volumes below 40 mL, LR-ADP revealed reduced aggregation. As a result, it is recommended to monitor and record volumes of LR-ADP used for pediatric transfusion. Moreover, once LR-ADP attain a volume of 50 mL or less on Day 4 or Day 5 of storage, consider discarding these products until their in vivo efficacy can be studied.