APC and myeloproliferative disorder: Plasma levels of free thrombin and APC were higher in the MPN+ than in the MPN− cohort, with 0.49 vs. <0.46 pmol/L (p = 0.0057), respectively, 1.23 vs. 0.58 pmol/L (p = 0.0122), and in healthy controls (vs. <0.46 pmol/L, p = 0.0012; vs. 0.54 pmol/L, p = 0.0035).