Livingstone Blood Collection Plastic Tube with K2 EDTA are used for whole blood hematology determinations, immunohematology testing, and blood donor screening. EDTA is used to anticoagulate whole blood for haematological investigations as the cellular components of the blood are particularly well preserved by EDTA. It works as an anticoagulant as it forms complexes with metal ions such as calcium, therefore inhibiting the coagulation cascade.