According to the needs of different testing programs in the laboratory department, the retention of urine specimens varies, and we classify urine specimens into morning urine, random urine, and 24-hour urine according to the time of collection. Here we will understand the specific requirements and methods for the three types of specimens: Morning urine: the first urine collected early in the morning, for routine urine and urine pregnancy test, because of the concentration and formation of fractions as well as urine HCG content is higher, increasing the detection rate of positive. It is mostly collected from inpatients, but if outpatients cannot be collected in the hospital, they can use a clean container to collect morning urine at home and bring it to the hospital in time for testing. Random urine: A urine specimen taken at any time, mostly from outpatients, can be used for routine testing. 24-hour urine: Urine specimens are collected at the beginning of the clock by emptying the urine and collecting the urine specimens for the corresponding period of time, mostly used for urine biochemistry tests. A large, clean, dry container with a lid is prepared. Patients urinate at 7:00 a.m. and discard, and each subsequent urine is collected in the container until the last urine voided at 7:00 a.m. the next morning, requiring all urine within 24 hours to be retained in the container. The total amount of urine for 24 hours was measured and expressed in milliliters (mL) or liters (L). Then all urine was mixed thoroughly and 4 mL was poured into a 10 mL urine tube with a cap. Notes on urine retention: 1. The best time for specimen delivery is within 30 minutes, and the longest time should not exceed 2 hours, otherwise it will cause: (1) bacterial growth and multiplication in urine: ① urea enzymolysis, so that urine pH rises and organic fraction is destroyed (tubular decomposition, red blood cell lysis); ② glucose is degraded, so that pathological glycosuria disappears; ③ bacterial bacteriophage protein and pathological protein urine interfere with each other. (2) The chemical components in urine (urobilinogen) can be denatured and decomposed due to the long storage of urine; urine salts precipitate crystals due to long storage and interfere with microscopic examination, thus affecting the judgment of the results of urine. 2, the presence of drugs and various disinfectants should be avoided in the container to prevent the destruction of various organic component forms and hormonal activity. According to the requirements of different items, choose whether to use sterile containers and whether to keep them refrigerated. 3.It is best to clean the urethral orifice and vulva before specimen retention, and avoid contamination by mixing menstrual blood, leukorrhea, semen and feces during specimen retention. 4, Retain fresh clean middle urine (continuous urination without interruption, at this time intercept the urine of the middle discharge, you can tell the patient to count three seconds from the beginning of urination, and then immediately receive urine), retain about 12mL as the specimen for testing, pour into the disposable urinary tube. 5. 24-hour urine that is, all urine for 24 hours is strictly controlled. Because the concentration of various substances in human urine varies at different times, for example, catecholamines, 17-hydroxysteroids, electrolytes, etc. have the lowest content in urine in the morning, while the content is higher in the afternoon, so all urine within 24 hours must be strictly retained. 24-hour urine specimens are placed in a cool and ventilated place for storage during collection to reduce microbial growth and maintain constant urine pH.