Background: PLT concentrates are licensed for use up to a maximum of 5 days of storage. Increasing storage to 7 days would improve the logistics of supply and have the potential to reduce wastage.
Study design and methods: PLTs were prepared from CP2D blood with standard procedures (n = 16) and then WBC-reduced. Sampling was carried out at 3, 5, and 7 days for PLT count, pH, aggregation to ADP and collagen, hypotonic shock response, Kunicki morphology score, thromboelastogram response, pO2, and pCO2, and PLT activation (CD62) was carried out by flow cytometry. Additionally, PLTs stored for 7 days were transfused into thrombocytopenic patients, and the CCI was calculated.
Results: Some of the in vitro tests such as the aggregation response to single stimuli showed decreased values with time. The hypotonic shock was well maintained for 7 days (77%-68%); the Kunicki morphology score showed progressive shape change (300 to 164). The CCI of 7-day PLTs averaged 16,000 (n = 9).
Conclusions: The data indicate acceptable in vitro PLT function at 7 days. Transfusion of the 7-day-old CP2D PLTs resulted in an appropriate posttransfusion increment in thrombocytopenic patients. Random donor PLTs collected into CP2D can be successfully stored for 7 days before use.