EDTA tube is widely used in clinical hematology as well as various kinds of blood cell test instruments. The interior of the tube wall is coated with either K2EDTA or K3EDTA. The EDTA binds calcium ions thus blocking the coagulation cascade.
EDTA K2 K3 tube contains EDTA anticoagulant. Compared with other anticoagulants, EDTA anticoagulant has little impact on the agglutination of blood cells and the morphology of blood cells. Therefore, EDTA salt (2k, 3k, 2Na) is usually used as anticoagulant. EDTA salt can combine with calcium ions in blood to form chelates, so as to prevent blood coagulation.