The order of blood collection is blood culture first, followed by sodium citrate anticoagulant tube, serum collection tube, heparin anticoagulant tube, EDTA anticoagulant tube, and glucolysis inhibitor tube. A variety of blood tests require venous blood collection, and different tests require different additives, so usually after a venipuncture, multiple tubes of blood will be collected and sent for testing, and the order of blood collection should follow the principles of sterile tubes first, as well as no additives first, then additives, and additives that have a small impact on the test in front of the additives, and those that have a large impact on the test in the back. First, blood culture tubes are used; then blue and black tubes with sodium citrate anticoagulation are used; then red and yellow serum tubes are used; and then green tubes with heparin anticoagulation are used for biochemical tests, such as liver and kidney tests. Purple EDTA (ethylenediaminetetraacetic acid) anticoagulation tubes are used for routine blood tests, and gray glucolysis inhibition tubes are used for blood glucose tests. Generally, you need to select the test items according to your condition, choose the blood collection tubes you need according to the test items, and collect the blood in order.