You can check urine routine, kidney function and ultrasound of urinary tract for bad kidney. Kidney diseases include many kinds of diseases, so the methods of examination used are different. If it is nephritis or urinary tract infection, routine urine examination is mainly performed to observe whether there is urine protein, red blood cells and white blood cells. If there is urine protein and red blood cells, it may be nephritis, and if the white blood cells are positive, it may be a urinary tract infection. If it is renal failure, you need to check the kidney function and observe if there is a significant increase in creatinine and urea. If stones, tumors or hydronephrosis in the urinary tract are suspected, then a urinary ultrasound examination should be performed in this case. Of course, all of these diseases have some clinical symptoms, so you can choose the specific examination items according to the symptoms to determine the disease in general and avoid wasting too many examinations.