Sodium citrate 1:9 ( blood coaguation tube marked 9NC , light blue)
Sodium citrate functions as anti-coaqulant via chelation with calcium in blood.
Concentration of sodium citrate is 3.22 and the volume ratio of anti-coagulant
vs  . blood is to. It is mainly used for coagulation test  ( prothobin time thrombin 
time , active partial thrombo plastin time , fibrinogen