CE&ISO certified professional manufacturer of medical supplies lab consumables vacutainer since2009-Hebei Vacuum blood collection tubes are applicable to the clinical blood test and the blood cells analysis The internal walls of the tubes are coated with different additives designed to stabilize and preserve the specimen prior to analytical testing *Red: Non-additive - Serum *Red: Clot Activator-Serum *Yellow: Gel & Clot Activator -Serum *Purple: ETDA K2 / ETDA K3 - Whole blood *Black: 3.8% Sodium Citrate (1:4)- Whole blood *Blue: 3.2% Sodium Citrate (1:9)- Whole blood or Plasma *Green: Lithium Heparin / Sodium Heparin-Plasma *Grey: Glucose - Plasma