Isolation and Characterization of Circulating Microparticles by Flow Cytometry.

Microparticles are small fragments (0.1-1.0 μm) of cellular membrane which are shed by cells under conditions of stress. As levels of circulating microparticles are elevated in disease, there has been significant interest in their assessment and quantification under pathological conditions. Here we describe a protocol for the isolation of microparticles from plasma samples and their characterization/quantification by flow cytometry. This assay has been employed for the assessment of microparticle levels in both human and animal plasma and may also be modified for the characterization of microparticles from culture media or from other biological samples (i.e., urine).