The invention includes methods of inhibiting blood coagulation using antibodies that provide superior anti-coagulant activity by binding native human TF with high affinity and specificity. Methods of the invention can effectively inhibit blood coagulation in vivo. Antibodies used in the methods of the invention can bind native human TF, either alone or present in a TF:VIIa complex, effectively preventing factor X binding to TF or that complex, and thereby reducing blood coagulation. Preferred antibodies used in the methods of the invention specifically bind a conformational epitope predominant to native human TF, which epitope provides an unexpectedly strong antibody binding site.