1, together with the blood collection personnel to confirm the name, gender, test purpose and other basic information of the subject; 2, to take a comfortable position, often sitting, to expose the blood collection site, commonly upper limb elbow superficial vein; 3, the blood collector will be placed above the blood collection site, and knotted around the arm a circle, the patient needs to clench and relax the fist several times to fill the vein; 4, the end of the blood collection, the patient needs to loosen the fist, with sterile cotton swab light pressure on the puncture site for 3 minutes.