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Updated: Jun 26, 2026
Routine Screening Method for Microparticles in Platelet Transfusions
Published on: January 31, 2018
The characterization and impact of microparticles on haemostasis within fresh-frozen plasma
A S Lawrie1, P Harrison, R A Cardigan
1Haemostasis Research Unit, Department of Haematology, University College London, London, UK. andrew.lawrie@ucl.ac.uk
Background:
We have previously demonstrated that clot formation in fresh-frozen plasma (FFP) is influenced by the presence of microparticles (MP). In this study, the cellular source(s), properties and influence of MPs on clot formation within FFP were further characterized.
Methods:
Fresh-frozen plasma was prepared after an overnight hold of whole blood at 4 degrees C. We examined the effect of a 0.2 microm filtration device designed to remove cellular MPs on thrombin generation test (TGT) and Thrombelastography (TEG(R)) as well as clotting factors and physiological inhibitors: prothrombin time (PT); activated partial thromboplastin time (APTT), fibrinogen (Fg), factor VIII (FVIII), von Willebrand factor antigen (VWF:Ag), antithrombin III (AT-III) and protein C (PC). MPs were measured using a functional assay and also by flow cytometry.
Results:
Microparticle levels by functional assay were reduced by filtration (pre- 5.11 vs. post- 4.43 nmol/l phosphatidylserine equivalent, P < 0.0001). Flow cytometry showed that the most numerous MPs were derived from red blood cells, with ~87% binding annexin V, most of which (94%) were removed by filtration. MP removal had minimal effect on the PT, APTT, Fg, VWF:Ag, AT-III or PC or FVIII, but a major effect on TGT (endogenous thrombin potential: pre- 1722 vs. post- 990 nM thrombin, P < 0.0001; peak thrombin: pre- 91 vs. post- 44 nM thrombin, P < 0.0001), which in turn reflected the changes seen in TEG(R), where post-filtration clots started forming more slowly and the rate of clot formation was reduced.
Conclusion:
These data suggest that MPs contribute towards clot formation in FFP.
Insights
Microparticles (MPs) in fresh-frozen plasma significantly influence clot formation. Removing MPs via filtration reduced thrombin generation and slowed clot formation, suggesting MPs contribute to clotting in FFP.
Area of Science:
- Hematology
- Biochemistry
- Biophysics
Background:
- Clot formation in fresh-frozen plasma (FFP) is influenced by microparticles (MPs).
- Previous studies indicated MP influence on FFP clotting.
- This study further characterized the cellular source, properties, and impact of MPs on FFP clot formation.
Purpose of the Study:
- To characterize the cellular source and properties of MPs in FFP.
- To investigate the influence of MPs on clot formation dynamics in FFP.
- To assess the effect of MP removal on hemostatic parameters in FFP.
Main Methods:
- FFP was prepared from whole blood held overnight at 4°C.
- A 0.2 µm filtration device was used to remove cellular MPs.
- Thrombin generation test (TGT), Thrombelastography (TEG®), and assays for clotting factors (PT, aPTT, Fg, FVIII, VWF:Ag) and inhibitors (AT-III, PC) were performed.
- MPs were quantified using a functional assay and flow cytometry.
Main Results:
- Filtration significantly reduced MP levels (pre- 5.11 vs. post- 4.43 nmol/l PS eq., P < 0.0001).
- Red blood cells were the primary source of MPs (~87% annexin V positive), with 94% removed by filtration.
- MP removal minimally affected clotting factors but significantly reduced TGT (endogenous thrombin potential: 1722 vs. 990 nM, P < 0.0001; peak thrombin: 91 vs. 44 nM, P < 0.0001) and altered TEG® parameters, indicating slower clot initiation and reduced formation rate.
Conclusions:
- MPs are a significant contributor to clot formation in FFP.
- Red blood cell-derived MPs play a key role in enhancing thrombin generation.
- Filtration of MPs alters FFP's hemostatic potential, impacting clot kinetics.
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