Uric acid is the end product of purine metabolism and is mainly produced by the enzymatic breakdown of nucleic acids and other purine analogues from cellular metabolism as well as purines from food. Enzymatic serum (plasma) uric acid concentrations in adults range from 150 to 416 μmol/L in men and 89 to 357 μmol/L in women, and approaching men after menopause, there are large fluctuations in blood uric acid, which should be monitored repeatedly. After 5 days of purine restricted diet, uric acid excretion exceeding 3.57 mmol (600 mg) per day can be considered as increased uric acid production. Uric acid concentration higher than normal is considered as high uric acid, and there are two main types of causes: increased uric acid production and decreased uric acid excretion, and sometimes both of them coexist. Increased uric acid production: This includes both high purine dietary intake and increased metabolic production of endogenous purines. Food-induced uric acid production is proportional to the purine content of food, and purine-rich foods include animal liver, kidney, anchovies, etc. The increase of endogenous purine metabolism in the body is mainly related to the synthesis and decomposition of purine. Decreased uric acid excretion: About 2/3 of uric acid is excreted through the kidneys, and the remaining 1/3 is excreted through extrarenal pathways such as the intestinal tract and biliary tract. About 90% of patients with persistent hyperuricemia have defects 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 crystallization. The uric acid concentration is lower than normal, mainly due to various causes of impairment of renal tubular reabsorption of uric acid, loss of uric acid in large amounts, and reduced uric acid production due to severe impairment of liver function. Such as acute hepatic necrosis, hepatomegaly, etc. In addition, chronic cadmium poisoning, use of sulfonamide and high dose glucocorticoids, congenital defects in xanthine oxidase and purine nucleotidase, which are involved in uric acid production, may also cause a decrease in uric acid. Therefore, high or low uric acid concentration is abnormal and should be paid attention to, promptly seek medical attention, find the cause and actively treat.