Leukocyte lipase is a hydrolase, an enzyme that hydrolyzes indolyl esters to produce indolyl phenols and organic acids, which are further oxidized to an indigo color, and this principle can be used to monitor leukocytes in the urine. If the urine is positive for leukocyte esterase, it often indicates the presence of an abnormal increase in leukocytes, which can indicate the presence of a urinary tract infection. Common causes of urinary tract infections are bacterial infections, such as E. coli, S. pyogenes, Staphylococcus, etc. When the body’s immune system is low, retrograde infection via the urethra and further development of the bladder mucosa can lead to a renal pelvis infection. For urinary tract infections to be actively treated, you can generally use sensitive antibiotics for anti-inflammatory treatment, if necessary, through the urine bacterial culture drug sensitivity test to guide the clinical use of drugs.