Whole blood TXB2 production and in vitro effect of NS-398 versus aspirin. Box-whisker plots of serum TXB2 values from 14 ET patients after incubation of whole blood samples in vitro with vehicle (n = 14), NS-398 (n = 13), or aspirin (n = 12). *P < .001 versus vehicle; #P < .001 versus NS-398.