Tube is mainly used for coagulation studies in medical fields and laboratories. Plastic Made Coagulation Vacuum Tube is filled with buffered tri-sodium citrate solution and comes with a blue coloured tight fitted cap. The Coagulation Vacuum Tube has the mixing ratio of one part citrate to nine parts blood with possibility of high accurate blood-to-additive ratio. The Coagulation Vacuum Tube is available in sizes of 13 X 75 mm and 13 X 100 mm and has maximum vacuum tolerance of ± 10%. Plastic Made Coagulation Vacuum.