Elevated FVIII accelerates the onset of platelet aggregation when initiated with low, but not high, TF. Platelet aggregation in human PRP spiked with human FVIII (final concentrations indicated) was triggered by recalcification and addition of TF and monitored by turbidity as described in “Methods” and Machlus et al.²²  Graphs shown are from one experiment, representative of 4 to 6 experiments at each TF concentration. (A) High TF (1:30 000 Innovin, final). (B) Low TF (1:200,000 Innovin, final). Note difference in x-axis (time) scaling in panels A and B. (C-D) Quantification of lag time data initiated with high (C) and low (D) TF, respectively. Graphs show mean ± SEM. *P < .05 versus 100% FVIII.