1. The blood sampling needle slips out of the blood vessel: Generally, the blood sampling needle is not fixed or not fixed firmly, which is caused by pulling. Treatment measures: After successful puncture, the needle handle was fixed with tape to prevent the needle handle from sliding, resulting in the needle prolapse.

2. Hemolysis: the vacuum negative pressure is large, and the blood quickly flows into the test tube during the operation, and the hemolysis is caused by the collision between the blood and the wall of the test tube; When the vacuum negative pressure tube with anticoagulant is collected, it swings too violently during the blood collection process, resulting in hemolysis. Treatment measures: the vacuum tube should be tilted 45°, and the inclined plane of the blood sampling needle should be close to the wall of the test tube, so that the blood flows slowly.

3. The vacuum negative pressure tube does not suck blood smoothly or does not suck blood: the main reason is that the strong negative pressure in the tube causes the inclined plane of the front needle to be close to the blood vessel wall or because the vacuum in the tube is not enough. Treatment: Gently move the needle with a hand needle wing and replace the unused blood test tube.