Activity and concentrations of FXIII after infusion of 20, 50, or 75 U/kg rFXIII in patients with FXIII deficiency. (A) Individual FXIII plasma activity. (B) Individual total FXIII-A₂ plasma concentrations. (C) Individual FXIIIA₂ B₂ heterotetramer concentrations. (D) Individual FXIII-free B subunit concentrations.