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Microparticle profile and procoagulant activity of fresh-frozen plasma is affected by whole blood leukoreduction rather than 24-hour room temperature hold


  • Kasey Sze-Kei Chan,

    1. Research and Development, Australian Red Cross Blood Service, Melbourne, Victoria, Australia
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  • Rosemary L. Sparrow

    Corresponding author
    1. Research and Development, Australian Red Cross Blood Service, Melbourne, Victoria, Australia
    • Address reprint requests to: Rosemary L. Sparrow, PhD, c/o Department of Immunology, Monash University, Alfred Medical Research and Education Precinct, Commercial Road, Melbourne, Victoria 3004, Australia; e-mail:

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  • The Australian government fully funds the Australian Red Cross Blood Service for the provision of blood products and services to the Australian community. This work was funded in part by NIH Grant 1R01 HL095470-01A1.



Microparticles (MPs) are small phospholipid-containing vesicles that have procoagulant properties. MPs are thought to contribute to the hemostatic potential of plasma. This study investigated the effects of whole blood (WB) hold time and leukoreduction (LR) on the MP profile and hemostatic potential of fresh-frozen plasma (FFP).

Study Design and Methods

WB units (n = 12) from healthy donors were divided into two pairs and each pair was held at 20 to 24°C for 6 or 24 hours. At the designated hold time, 1 unit from the pair was LR while the other unit was not LR. FFP was prepared by standard procedures, aliquoted, and frozen. The MP content was determined by flow cytometry using an absolute count assay and specific labels for red blood cells (CD235a), platelets (CD41), and phosphatidylserine (PS). The hemostatic potential was determined by thrombelastography (TEG) and coagulation factor assays.


Compared to non-LR-FFP, LR-FFP had significantly lower numbers of MPs, particularly CD41+ MPs and PS-positive MPs (p < 0.03). LR-FFP, compared to non-LR-FFP, had a slower clot formation time (p = 0.002); lower clot strength (p < 0.001); and lower Factor (F)VIII, FXII, and fibrinogen levels (p < 0.01). With longer WB hold time, the TEG profile was unchanged, although FVIII levels were decreased as expected (p < 0.01). On average FFP units met quality requirements.


LR of WB resulted in lower hemostatic potential of FFP in conjunction with depletion of MPs and coagulation factors. Longer WB hold time did not significantly affect the hemostatic potential of FFP as measured by TEG. Acceptable hemostatic quality was maintained for all FFP processing conditions studied.