The skin test injection site is usually chosen between the medial wrist and elbow joints, the triangle between the midclavicular line and the sternum, the lower 1/3 of the medial calf and the medial upper buttock, etc. The choice of the skin test site is based on the characteristics of the injection site and the degree of pain. 1. between the medial wrist and elbow joints: the reason for choosing the site between the medial wrist and elbow joints is More peripheral nerve fibers in the distal upper limbs, less resistance to needle entry, low sensitivity to pain, and easier for patients to accept; 2, the triangular area between the midclavicular line and the sternal line bilaterally: the skin there is thinner and lighter in color, and the area is adjacent to the heart area, so edema rarely occurs, with wide exposure and light pain; 3, the lower 1/3 of the inner calf: this area is suitable for those with severe edema, and the color of the calf area and The color and fineness of the calf area depends on the person, relatively lighter skin tone and smoother skin are easier to identify the blood vessels and the pain will be relatively small; 4. Upper inner hip: the distribution of vascular nerve endings on the inner hip is less, more suitable for children, the hip is easier to expose and the skin is tighter, the operation is more convenient and can reduce the pain. In addition, it should be noted that if the patient’s allergic symptoms are in the acute phase, the skin test should be suspended; antihistamines and corticosteroids should be stopped 1 week before the skin test; the patient’s skin test site should be free of eczema, urticaria or other skin damage.