Renal tubular function test methods include phenol red excretion test, renal concentration and dilution test. 1. Phenol red excretion test: 25% of excretion in 15 minutes (20% above 50 years old) and 55%～75% of total excretion in 2 hours in healthy people. This test can be used as a rough indicator of the excretory function of the proximal renal tubule. 2. Renal concentration and dilution test: that is, under specific daily dietary conditions, observe the changes in the patient’s urine volume and urine specific gravity, as an indicator to determine the function of the distal renal tubules. Under normal circumstances, the ratio of daytime urine volume to nocturnal urine volume is 3~4:1; 12-hour nocturnal urine volume should not exceed 750mL; the highest specific gravity of urine should be above 1.020. If patients find abnormalities in renal tubular function, it is recommended to go to regular hospitals in a timely manner, improve the examination to clarify the cause of the disease, and then give targeted treatment or therapy under the guidance of the doctor.