Platelet and Platelet-derived Microparticle Surface Factor V/Va Binding in Whole Blood: Differences between Neonates and Adults

Platelet-derived microparticles (PDMP) appear to play a major role in the generation of procoagulant activity. In this study, we describe a novel flow cytometric method that allows direct evaluation of the procoagulant activity of PDMP and platelets in the physiological milieu of whole blood. The percent PDMP generated in response to calcium ionophore A23187 and calcium was increased in preterm neonates (67.5 ± 3.4%, mean ± S.E.M., n = 8, p