Significance of EDTA and Sodium Citrate in Blood Preservation: A Reaction Mechanism with Calcium as Substrate

Coagulation or clotting is the process by which blood transforms from a liquid to a gel resulting in the formation of a blood clot or fibrin mesh. It may result in hemostasis, which is a phenomenon of stopping blood loss from a damaged vessel followed by healing mechanism. Platelets and proteins in plasma (the liquid component of blood) collaborate to stop the bleeding by creating a clot on the area damage. The proper regulation of the coagulation cascade, which is essential for maintaining hemostasis, is greatly aided by calcium ions. Ethylenediaminetetraacetic acid (EDTA) is a well-known anticoagulant since early 1950s and it has certain advantages over other anticoagulants such as sodium citrate and heparin. Over a century, sodium citrate has been used as a balancing agent for blood and blood products as an anti-coagulation, presumably by sequestering calcium ions in vitro (Proescher and Nolan, Progress in blood preservation. PubMed Central [1]). Anticoagulation of blood without chelation can be achieved by inhibiting the contact pathway of corn trypsin inhibitor (CTI). The cascade reactions of ethylenediaminetetraacetic acid and sodium chloride salt with blood results in anti-coagulation effect which is indeed important for sample preservation. The paper discusses the reaction mechanism and the results for EDTA and sodium citrate, respectively, and suggesting the best among them.