Applying to the acquisition of high-quality serum, specimens for biochemical, immunological and serum clinical examination. Serum separation gel is a kind of semi-solid inert gel, composed of several compounds and synthesized by medical polymeric material. After blood is centrifugal, the specimen can be separated into serum top, separation gel middle and blood corpuscle lower. In the middle of the tube, a thick layer of separation gel can completely isolate serum from the blood corpuscle, to ensure purity of serum.