1. When urinary tract infection occurs, there are pathogenic bacteria in the urine, then the leukocytes will engulf the pathogenic bacteria, which will cause the number of leukocytes in the urine to rise, and the leukocytes that have engulfed the pathogenic bacteria will become pus cells, which will be excreted with the urine, and the patient will have symptoms such as frequent urination, urgent urination, painful urination, cloudy urine, or what drugs are sensitive. The patient will have symptoms such as urinary frequency, urinary urgency, urinary pain, cloudy urine or back pain, fever, etc. Further anti-infection treatment is needed, and urine culture examination can also be performed to further clarify what bacterial infection is and what drugs are sensitive. 2, it can also be because the urine has been placed for too long and spoiled, or the urine is contaminated by other pathogenic bacteria, which will cause the number of white blood cells in the urine to rise, without any urinary tract infection symptoms. The symptoms of urinary tract infection will not occur, and there will be no reaction such as frequent and urgent urination.