1.Inner tube in PP, outer tube in PET, multiple barriers, lower both water and air permeability, ensure the test accuracy of blood coagulation

2.Special process of unique stress membrane treatment for the inner wall, try to avoid extrinsic coagulation mechanism caused by the tube material being activated

3.Application of patent technology prevents coagulation factors & platelets are activated, provides condition to get believable and constant test results for PT and APTT