The kidney is one of the most important organs in the human body, and its function is mainly to secrete and excrete urine and waste products. Related diseases, infections, drugs and toxins can cause kidney damage, which is mainly manifested as abnormalities in kidney function test indicators. There are several clinical methods to assess kidney function: Routine urine examination is one of the most commonly used methods of kidney function examination clinically, reflecting the severity and progress of kidney and urinary tract diseases based on the presence or absence of red blood cells, white blood cells, protein, bilirubin and other substances in urine. The cost is about $20. In addition, in addition to urine examination, clinical use of venous blood can also be used to test biochemical indicators of kidney function, these indicators can reflect the glomerular filtration function and tubular reabsorption and other functions, thus indirectly reflecting the function of the kidney. The cost of three renal function tests, including creatinine clearance, creatinine and urea nitrogen, is about 30 RMB; the cost of five renal function tests, which generally include creatinine, urea nitrogen, creatinine clearance and some electrolytes and acid-base, is about 60 RMB. Due to the differences in testing methods and items, the cost of the test may vary from hospital to hospital. Therefore, when patients have symptoms such as frequent urination, urgent urination, painful urination, foamy urination, blood in urine and pain in the kidney area, it is recommended to consult the nephrology or urology department, and the specialist will choose the test items according to the specific condition for further diagnosis and treatment.