Association between FIXa:AT with other contact and intrinsic pathway protease:serpin complexes. Spearman correlation coefficients are shown for FXIIa:C1 inhibitor (A), FXIa:C1 inhibitor (B), kallikrein:C1 inhibitor (C), and FXIa:α1-antitrypsin (D). Samples from 2 patients were not processed because of critical preanalytic issues (low volume).