Uric acid is the end product of purine metabolism, mainly produced by the cell metabolic breakdown of nucleic acids and other purine-like compounds and purines in food by the action of enzymes. Adult enzyme serum (plasma) uric acid concentration is 150~416μmol/L in men, 89~357μmol/L in women, and close to men after menopause. Uric acid concentration is higher than normal for high uric acid, there are two main types of reasons for increased uric acid production and decreased uric acid excretion, sometimes both co-exist. Increased uric acid production: mainly includes high purine dietary intake and endogenous purine metabolism increased production of two aspects. Food-induced uric acid production is proportional to the purine content of the food, and purine-rich foods mainly include animal liver, kidney, anchovies and so on. The body endogenous purine metabolism increased mainly related to the synthesis and decomposition of purine and other factors. Decreased excretion of uric acid: about 2/3 of uric acid is excreted through the kidneys, and the remaining 1/3 is excreted through extra-renal pathways such as the intestines and biliary tract. About 90% of patients with persistent hyperuricemia have a defect in renal processing of uric acid and show reduced uric acid excretion, including reduced glomerular filtration rate, increased tubular reabsorption, reduced tubular secretion and urate crystal deposition. Uric acid concentration is lower than normal value for low uric acid, mainly due to various reasons to the renal tubular reabsorption of uric acid function is impaired, a large number of urine loss, as well as severe damage to hepatic function of uric acid production is reduced. Such as acute hepatic necrosis, hepatomegaly. In addition, chronic cadmium poisoning, the use of sulfonamide and high-dose glucocorticoids, involved in the production of uric acid xanthine oxidase, purine nucleotidase congenital defects, etc., can also lead to a decrease in blood uric acid. Therefore, the normal value of uric acid adult enzyme serum (plasma) uric acid concentration of male 150 ~ 416 μmol / L, female 89 ~ 357 μmol / L, uric acid concentration is high or low are abnormal, need to pay attention to find out the cause of the problem, and active treatment.