There is no fixed evaluation standard for how much difference between 24h in and out volume is considered normal, but the normal adult 24h in and out volume is 2000-2500ml, the in volume includes drinking water, solid food water, metabolic endogenous water, etc., totaling 2000-2500ml, the out volume includes kidney excretion, colon excretion, respiratory evaporation, skin evaporation, etc., totaling 2000-2500mL, usually the 24h in and out volume is basically the same. The amount of 24h discharge is usually difficult to assess accurately, in different environments, different temperature conditions, different seasons, the amount of discharge will have a large change, such as the respiratory tract, skin route of the discharge will be relatively large, especially in the summer in high heat, high temperature working environment, the respiratory tract, skin discharge will be relatively large, while urine will be relatively reduced, the opposite in winter. Therefore, the calculation of 24h output and output is not easy to grasp, and needs to be combined with specific situations to make relatively accurate judgments. 24h output and output is mainly used as a basic reference for clinical infusion, such as calculating rehydration volume, or as a preliminary reference for renal function evaluation, and if renal function is to be evaluated, it can be examined by other more accurate methods, such as urinary routine, renal function examination, etc., and also isotope examination can be performed to accurately calculate glomerular filtration fraction.