No additive tube is used in blood collection and storage for biochemistry, immunology, serology, test of various kinds of virus and microelement in medical inspection. With special treatment of the inner surface, it’s extremely smooth for normal activity of thrombocyte and unhindered clotting, which prevents hemolysis or adhesion of blood corpuscle or fibrin to the inner surface. It can provide enough pollution-free serum samples for clinical test, and maintain the normal compositions of serum for a long time. Moreover, it’s helpful to serum reinspection with good repeatability. Time for complete clot retraction: 1.5-2h Centrifugation speed: 3500-4000r/m Centrifugation time: 5min Recommended storage temperature: 4-25℃.