1.Preparation supplies: ordinary plastic bucket or jug (or large-capacity Coke bottle, etc., with a capacity of 3000ml or more), preservative (such as toluene, etc., from the laboratory), precision measuring cylinder, timer (such as an alarm clock). 2, urine retention process: according to the doctor’s advice or your own work schedule, choose a good date for the start of urine retention. At 7:00 am on the same day (or slightly earlier or later), you must urinate once, whether or not you have the urge to urinate, and discard this urine (i.e., do not put it in the bucket), but all urine discharged 24 hours thereafter should be put into a plastic bucket (antiseptic is added to the bucket after it is filled with the first urine and shaken well). The next morning at 7:00 a.m. sharp (or depending on the 1st time, advance or postpone accordingly), whether or not you have an obvious urge to urinate, urinate once and load the discharged urine into a plastic bucket. Precautions: 1. During urine collection, diet and activities should be as much as possible as usual, do not engage in strenuous activities, avoid overexertion or infection, and avoid eating a high-protein diet. Female patients should avoid the menstrual period. 2. The first and last two urine treatments are the most critical, and it is highly recommended to set an alarm beforehand in order to urge yourself to handle it on time. Note that the first urine should be discarded, as it represents the urine from the previous 24 hours. 3. When urine is put into the bucket for the 1st time, you need to pour the preservative (provided by the testing department, depending on the test items, such as measuring 24-hour urine protein quantification, then toluene is commonly used) into the plastic bucket at the same time and shake well, then cover the bucket immediately (to prevent the preservative and urine from evaporating). You can also first collect the urine in a clean open bottle or basin, and then immediately transfer all the urine samples into a large plastic jug or Coke bottle with a funnel, etc., to facilitate carrying them to the clinic. 4.If you have a medical measuring cylinder, you can measure the 24-hour urine volume by yourself, but you should make sure that it is as accurate as possible and never estimate it arbitrarily. If you have difficulty in measuring, you can bring the entire urine sample to the hospital for measurement. 5, urine sent for testing specimen retention should be shaken or mixed all urine after a small amount of urine to test tubes to measure urine protein concentration (such as not mixed may be high or low), record the total urine volume, calculate the total urine protein excretion to prevent errors.