At present, urine examination of urine routine is gradually replaced by urine sediment analyzer, called urinalysis. Urinalysis in the clinical test method is easy to operate and fast, but there are some limitations, should be combined with urine appearance, odor, urine sediment microscopy and wet chemical method of detection in order to provide accurate and reliable clinical results and avoid misdiagnosis. So in the urine test patients should take the first morning urine, that is, the urine excreted early in the morning after waking up before breakfast and other exercise, emergency patients can be retained at any time. It is best to use clean, covered, non-polluted disposable urine cups, not beverage bottles, in which sugar and impurities can interfere with the results of the test. Urine specimens should avoid sunlight, menstrual blood, leukorrhea, mucus, feces and soot, sugar paper and other foreign substances mixed into the specimens to be tested promptly after retention, must be completed within 2 h after retention of the specimen testing (if not timely detection should be added specific preservative) to prevent storage for too long, bacterial growth and reproduction, cellular decomposition and other material destruction decomposition. The specimen for protein determination must be fresh, otherwise the pH of urine will be changed, when pH>8, it is easy to have false positive; when pH<3, it is easy to have false negative. When the prostate fluid, semen, leucorrhea is mixed in, it is easy to cause a false positive protein test. The determination of occult blood can cause false positives when certain bacteria produce oxidative enzymes in the case of urethral infection, and vaginal secretions and oxidative substances mixed in can cause false positives. Determination of leukocytes Vaginal secretions mixed with urine can cause false positives. High specific gravity urine, high glycosuria, room temperature below 20°C or less than normal reaction time can cause a low result. False-positive results can occur when the nitrite specimen is left too long or is contaminated. Urine erythrocyte bitemporal examination requires urine that has been retained in the bladder for more than 4 hours and is fresh, not brought to the hospital in a bottle but freshly retained and sent promptly for testing.