The dependence of lag time on shear rate is determined by the factor VII activation, TFPI- and AT3-mediated inhibition. Lag time is shown as a function of shear rate for normal plasma, and for plasma supplemented with factor VIIa, TFPI or AT3 as indicated in the legend. Addition of factor VIIa results in dramatic lag time decrease and the dependence becomes linear (blue). Addition of TFPI shifts the threshold to the region of lower shear rates (red). Addition of AT3 slightly increased lag time (dark yellow), compare to normal case. These results indicate that factor VII activation and extrinsic tenase inhibition with TFPI are indeed the controlling mechanisms determining behavior of coagulation in the presence of flow.