Kidney function includes broad and narrow sense: 1. Kidney function in the narrow sense: that is, often said to be laboratory kidney function, mainly laboratory blood tests. Kidney function indicators mainly include blood creatinine, urea nitrogen, uric acid and β2-microglobulin, retinol binding protein and electrolytes, such as potassium, sodium, chloride, calcium, phosphorus, and also carbon dioxide binding rate. The main purpose is to check the damage of kidney function, and also to check hyperuricemia. If the kidney function is abnormal, there may be an increase in creatinine and urea nitrogen, indicating that the kidney has been damaged, including β2-microsphere and retinol binding protein, mainly to check the early tubular function damage; 2. Broad kidney function test: other items may be done, such as urine routine, ultrasound and blood routine. It is mainly to see whether there is early kidney damage, but normal kidney function does not mean that there is no kidney problem. Some early kidney hazards may only have urine protein and hematuria, while kidney function, blood creatinine, urea nitrogen and color ultrasound are normal.