The recent availability of more precise assay techniques for the measurement of the natural anticoagulants, particularly total and free TFPI and protein S, encouraged us to monitor the fluctuations of natural anticoagulants in patients with sepsis, in a way that no study has done before, to find a possible explanation for why past trials administering natural anticoagulants to patients with sepsis failed. Here, PROS1 is linked to Sepsis.