HPC TF PCA does not require exogenous FVIIa. (A) Assessment of FXa generation by intact primary HPCs isolated from control mice (TF^flox/flox mice) or HPC^ΔTF mice. FXa generation by HPCs was assessed in the absence of exogenous FVIIa (see Methods). FXa levels are expressed as mean + SEM (pM/min) from 3 independent experiments. FXa generation was not detectable (ND) in cells from HPC^ΔTF mice. (B) PCA of intact control or HPC^ΔTF primary HPCs determined using a single-stage clotting assay using normal human pooled plasma or FVII-deficient human plasma. Data are expressed as mean fold change + SEM of control HPCs clotted with normal human pooled plasma from 3 independent experiments. *Significantly different from control HPCs clotted with normal human pooled plasma (P < .05).