There are 9 types of vacuum blood collection tubes, which are distinguished according to the color of the cover.
1. Ordinary serum tube red head cover
2. Orange cap for rapid serum tube
3. Golden head cap of inert separation gel to promote coagulation tube
4. Black cap of sodium citrate erythrocyte sedimentation test tube
5. Light blue head cap of sodium citrate coagulation test tube
6. Green cap of heparin anticoagulant tube
7. Light green cap for plasma separation tube
8. Potassium oxalate / sodium fluoride grey head cover
9. Purple head cap of EDTA anticoagulation tube