The precautions before checking kidney function are avoiding a lot of exercise, avoiding eating a lot of protein, and trying to need about 8 to 12 hours of fasting before the test. 1. Avoid large amount of exercise: creatinine and urea nitrogen in kidney function will be affected by exercise, large amount of exercise may increase the value, so avoid large amount of exercise. 2. Avoid eating a lot of protein: creatinine and urea nitrogen in kidney function will be affected by protein, so avoid eating too much protein, which will cause the result to be inaccurate. 3. Try to fast for about 8-12 hours before the test: Try to fast for 8-12 hours before the kidney function test, eating will cause the accuracy of the result to decrease. For specific precautions before renal function test, please consult your doctor and follow the doctor’s instructions to improve the test.