Blood Collection Tube EDTA K2 Vacuum Blood Collection Tube EDTA K2 SKG Medical EDTA tubes are for the examination of whole blood in haematology. Are offered as either K2 EDTA or K3 EDTA tubes.EDTA binds the calcium ions and therefore blocks the coagulation cascade. Erythrocytes, leucocytes and thrombocytes in an EDTA anticoagula