ATIII, which is essential to Heparin response may be low in many ICU patients, either hereditarily or acquired in response to sepsis, disseminated intravascular coagulation, liver diseases or exposure to extracorporeal circuits, e.g., CRRT, ECMO, etc. While ATIII supplementation is a common practice [37] and may improve Heparin response, the level of ATIII that classifies as sufficiently low to cause HR has not been defined. This evidence concerns the gene SERPINC1 and Sepsis.