Urinalysis is an important method for the diagnosis of many diseases, especially kidney disease. With the increase of urine examination items carried out in hospitals, the majority of patients should understand the common sense of different urine examinations and retain specimens correctly. 1, urine routine and urine sensitive kidney function: When collecting urine specimens for testing, it is best to use fresh morning urine to avoid deterioration of the sample and affect the test results; women should avoid menstruation and clean the vulva before retention to avoid contamination of the specimen. 2, 24-hour urine specimens: A small amount of preservative (such as 2% xylene) should be used, and urine should be collected at the beginning and up to the same time point on both days to avoid mismeasurement of urine. 3.Middle urine bacterial culture sample: Urine should stay in the bladder for more than 6 hours, do not drink before collection, do not take antibiotics, clean the vulva, minimize contamination, and do not mix disinfectants into the sample, resulting in false positives or false negatives. 4. Urine osmolality determination: The bladder should be emptied after 12 hours of water abstinence, and the urine should be retained for the 13th hour.