- First add 4 mg of either disodium or dipotassium EDTA salt to 100 ml of deionized water. then add 0.2 ml of this solution to clean vials, then put these vials in incubator or hot air oven for 1-2 hours at 60-80 Cْ , after that a white layer of anti-coagulant will be seen in the bottom. This bulb is for 3-4 ml of blood as it contains 8 mg of EDTA per vial.