It is a closed system in which the patient's blood goes directly from the vein into the tube through the rubber stopper present at the entrance of the tube without the blood being opened to the air. It is possible to collect many tubes using a single venipuncture. Three components are required for the vacuum system: double-ended needle, plastic holder or adapter, and vacuum sample tube. All components of the system should come from the same manufacturer to avoid difficulties with correct insertion of the needle and correct placement and removal of the tubes. Tubes used with the vacuum tube system for blood collection are known as vacuum tubes. With the vacuum tube, blood can be drawn directly from the vein into the tube without exposing it to air (closed system). This reduces accidental contact with blood. These tubes have a preset vacuum based on the volume of the tube and the type and amount of additive used in the tube. When the rubber stopper of the tube is penetrated with the back end of the needle into the needle/tube holder, blood is drawn into the tube from the vein using the vacuum. The vacuum in the evacuated tube allows the precise amount of blood to enter. Regardless of whether the anticoagulant in anticoagulant tubes is a liquid, powder, or spray within the tube, it must be allowed to fill to the finishing point. Not completely filling the