EDTA tubes used EDTA(K2) and EDTA(K3) as anticoagulants. They are widely used to collect blood for clinical hematology examination and suitable for blood cells analysis and determinations of blood groups.
Heparin is the only anticoagulant that should be used in a blood collection device for the determination of pH, blood gases, electrolytes and ion calcium.
Na Citrate was used as an anticoagulants in blood transfusion since year 1914. It continues to be used today in blood collection tubes and for the preservation of blood in blood banks.