Increased leukocytes in urine routine may develop into chronic urinary tract infection, perinephric abscess, renal papillary necrosis, or even bacteraemia, sepsis, etc. Increased leukocytes in the urine are seen in most cases in urinary tract infections and in a few cases in interstitial nephritis. For infections generally given antibiotics anti-infection treatment can improve, in most cases can be cured. If the patient is not treated in time, it may become a chronic urinary tract infection, which may cause chronic cystitis, chronic pyelonephritis, and especially chronic pyelonephritis, which may develop into chronic renal failure. Some patients with more serious urinary tract infections, especially acute pyelonephritis, may have complications such as perinephric abscess, renal papillary necrosis, etc., and may have complications such as bacteremia and sepsis. These conditions are more serious. Interstitial nephritis may lead to renal failure if it is chronic. Therefore, when elevated white blood cells in urine are found, the cause needs to be actively sought. Of course, the most common one is the urinary tract infection mentioned above, which needs to be treated with antibiotics against infection and also to exclude the possibility of acute interstitial nephritis.