Residual renal function can be calculated by residual renal urea clearance. Residual renal function can be calculated by residual renal urea clearance, which requires knowing the patient’s urine urea concentration, 24-hour urine volume, and serum urea concentration. The specific calculation method is [urine urea concentration (mg/dl) × urine volume (ml)]/[urine collection time (min) × serum urea concentration (mg/dl) × 0.9]. Clinical calculation of residual renal function is mainly to guide the development of dialysis program for hemodialysis patients. If the residual renal function is greater than 2 ml/min, dialysis can be performed 2 times per week with a total dialysis duration of not less than 10 hours. Otherwise, it needs to be dialyzed 3 times a week, and the dialysis duration is not less than 12 hours. Residual renal function needs to be checked and calculated by a specialist after going to a regular hospital for examination and treatment as prescribed by the doctor.