Urine placement time can be analyzed according to the specific time of the examination project, such as routine urine examination can be stored for two hours, 24 hours of urine protein determination can be stored for a day. 1. Routine urine examination: urine retention as much as possible to stay in the morning urine clean mid-range urine, should not be placed for too long, clinically recommended within two hours, if the urine is separated from the time is too long, may lead to corruption of the urine sample, affecting the results of the examination. 2. 24 hours of urinary protein determination: the retention of urine needs to be retained for 24h total urine, usually starting at 7:00 am to the next morning at 7:00 am last urination, after sufficient mixing to retain 5~10mL to send to the test, usually can be stored for a day. It is recommended that patients send the urine for examination in time after retention to avoid affecting the examination results, delaying the condition and causing other damages.