A routine urine test with three plus white blood cells indicates the possible presence of urinary tract infection or contamination of urine, and further tests are recommended to clarify this, as well as to further determine the patient’s own symptoms. For example, if the patient has frequent and urgent urination with three plus signs of white blood cells in urine, it is possible to diagnose the presence of urinary tract infection. Because the pathogenic bacteria are in the urine, the body’s leukocytes tend to enter the urine to engulf the pathogenic bacteria, causing the leukocyte count to increase and show a positive result. In this case, anti-infection treatment should be chosen according to the results of urine culture, and the white blood cells can return to normal levels after the inflammation subsides. If the patient does not have any conscious symptoms, it is possible that contamination was caused during the retention of the urine specimen, for example, the front part of the retained urine was affected by the external genitalia such as the male foreskin, which can cause an increase in the number of white blood cells, or the urine specimen was left for too long and its own bacterial decay occurred, which then caused the infection to grow and can also appear as an increase in the number of white blood cells. In this case, the patient does not have any conscious symptoms, and it is recommended to re-take a clean middle urine for review.