Pen-based blood sampling needle is not widely used in clinical practice.Its structure is a connected needle tube with sharp cutting edge on both ends. The middle and lower part of the needle tube is fixed on the needle base. The front end is called vein puncture needle and the back end is called blood collecting needle.In clinical practice, it is usually used in conjunction with needle holder and one-time blood vessel collection.
When in use, the blood collecting needle is rotated and fixed at the front end of the external cylinder of the needle holder for vein puncture. After success, the vacuum blood collecting vessel is inserted into the cavity at the back end of the needle holder to make the blade at the back end of the blood collecting needle pass through the blood blocking sleeve and Pierce through the vacuum tube rubber plug. Under the effect of negative pressure, the blood is extracted into the blood collection tube.This repetition can realize the collection of multi-tube blood samples.