The 24-hour urine retention requires attention, the urine of the first day at 6 am should be voided, the bladder must be empty at 6 am at this time. From this time onwards, the kidneys will keep producing urine, which will be stored in the bladder, and if you have the urge to urinate to drain, bring all this urine together first. Until 6:00 am the next morning, a full 24 hours. Whether or not there is an urge to urinate at that time, the bladder is emptied and all this urine is pooled into a clean container, which is the complete 24-hour retained urine specimen. The general requirement to take a portion of the complete specimen for testing is to mix this complete specimen thoroughly and then aspirate the amount needed to send it to the laboratory.