Preparation of cephalosporin skin test solution is the process of diluting the agent with 2 ml of saline and retaining 0.2 ml, adding saline to 1 ml and then draining 0.9 ml twice in succession and diluting to 1 ml. Take a cephalosporin, extract 2 ml of 0.9% sodium chloride solution to dissolve, and then extract 0.2 ml, add 0.8 ml of saline to 1 ml, shake the syringe up and down to shake the liquid, drain off 0.9 ml of liquid, leaving 0.1 ml; and then extract 0.9 ml of saline, shaking up and down to shake well, drain off 0.9 ml of liquid, and finally add saline to 1 ml shaking well, standby. It is worth noting that when preparing the skin test solution, it is important to look at the dose of the drug, so as not to miscalculate and lead to changes in the concentration of the skin test solution. Skin test solution should be prepared and used now, and the concentration and dose must be accurate. The concentration of the skin test solution should also follow the instructions of the drug, do not adjust the concentration of the skin test solution.