Glomerular filtration rate calculated by renal function test is relatively accurate, but there may be some errors, such as affected by age, diet, exercise and so on. Glomerular filtration rate refers to the amount of filtrate produced by the two kidneys per unit of time, which is used for the early understanding of renal function decline, for assessing the degree and development of renal unit damage, etc. It is usually calculated by blood creatinine and urine creatinine. However, the calculated glomerular filtration rate may be affected by factors such as age, gender, body weight, etc. Meanwhile, if the diet is rich in protein and the muscle catabolism is accelerated after exercise, it will also affect the creatinine level, so it will make the calculated glomerular filtration rate have a certain degree of error. Therefore, if patients want to calculate glomerular filtration rate, they should avoid eating protein-rich food, avoiding strenuous exercise and so on. If the glomerular filtration rate is found to be lower than normal level, it is recommended to consult a doctor in time and improve the relevant examination under the doctor’s guidance, and then treat the symptoms.