The presence of significant leukocyturia that is not accompanied by evidence of bacteria in the urine on standard microscopy or urine culture. Common noninfectious causes include contamination of the urine sample (e.g., by vaginal leukocytes), glomerular or tubulointerstitial disease, and inflammation of or trauma to the lower urinary tract (e.g., due to uroliths, urinary catheterization). Certain infections (e.g., gonorrhea, chlamydia, herpes genitalis, trichomoniasis, urogenital tuberculosis, schistosomiasis) can also cause sterile pyuria.