Anticoagulant Tube. Sodium citrate 9 to 1 tube is a kind of anticoagulant tube used for coagulation factor determination, used in clinical medicine to test the coagulation mechanism, PT, APTT, thrombosis, it is made of sodium citrate and anticoagulant mixed according to a certain ratio, the ratio of anticoagulant to blood is 1 to 9, which can effectively prevent blood from coagulating, making the results of coagulation factor determination more accurate and reliable.