Platelet removal by single-step centrifugation.

The study of extracellular vesicles (EVs) in plasma requires removal of cells including platelets. At present, a two-step centrifugation protocol is recommended and commonly used. A simpler protocol that is less operator dependent is likely to improve the quality of plasma samples collected for EV research. The objective of this study is to develop an easy, fast and clinically applicable centrifugation protocol to produce essentially platelet-free plasma with a high yield for EV research. We compared the two-step centrifugation protocol to a single-step protocol at 5,000 g for 20 minutes. The removal of platelets was computationally predicted and experimentally validated. Flow cytometry was used to detect residual platelets and platelet-derived (CD61+) EVs. The single-step protocol at 5,000 g (i) is less laborious and approximately ten minutes faster, (ii) removes platelets as effective as the two-step centrifugation protocol, and (iii) has a ~ 10% higher plasma yield, whereas (iv) the recovery of platelet-derived EVs is comparable. For future research on plasma EVs we recommend the newly developed, easy and fast single-step protocol for preparation of platelet-free plasma for research on plasma biomarkers including EVs.