Normal blood uric acid level is 150-416μmol/L in adult males and 89-357μmol/L in adult females. 422μmol/L is higher than the upper limit of the normal reference range, which may be caused by factors such as genetic or enzyme defects, diet, diseases and drugs. 1. Genetic or enzyme defects: familial juvenile hyperuricemic nephropathy, increased activity of ribose phosphate pyrophosphate synthetase, hypoxanthine-guanine phosphoribosyltransferase defects, and other congenital enzyme defects or genetic and other factors may lead to elevated uric acid. 2. Diet: large intake of seafood, animal offal, broth and other high-purine diet, drinking alcoholic beverages, high-sugar diet and other factors may lead to excessive production of uric acid and cause the patient’s body uric acid level increases. 3. Diseases: hemolytic disease, erythrocytosis, acute and chronic leukemia and other blood system diseases and renal function disease, renal tubular disease can also lead to increased levels of uric acid in the body. 4. Drugs: Diuretics such as furosemide, hydrochlorothiazide and non-chlorosartan, low-dose aspirin, tacrolimus, cyclosporine A, tobacco acid, vitamin B12 and other drugs may lead to elevated uric acid. There may be other reasons for blood uric acid 422μmol/L. Patients are advised to go to the endocrinology department and rheumatology department of regular hospitals for detailed consultation.