Gel can thoroughly separate the blood cells and plasma, the ... Measurement(cm)GD030LHGGreen cap,Heparin Lithium+Gel,13×75mm,3ml120048×38×20GD050LHGGreen cap,Heparin Lithium+Gel,13×100mm,5ml120048×38×25Gel & ... at the bottom of the tube, there is some gel for separating plasma and blood cells, preventing substance from exchanging ... so that well meets the quality requirement of retest. Gel & Heparin Tube