Sterile Pyuria

Excerpt

Sterile pyuria is a medical condition characterized by the persistence of leukocytes in urine without bacteriuria. Pyuria is characterized by a urine sample containing greater than or equal to 10 white blood cells (WBCs) per mm³, unspun urine with more than 3 WBC per high power field (WBC/HPF), or a urine dipstick analysis showing leukocyte esterase or nitrites. Sterile pyuria occurs when any of these criteria are met without significant bacteriuria on urine culture, defined as greater than or equal to 10⁵ colony-forming units (CFUs) per mL.

Advanced testing methods, such as next-generation sequencing (NGS), have shown that sterile pyuria may not necessarily indicate the absence of bacteria. Research by Wolfe et al has suggested the existence of bacteria in the urinary tract that may constitute a natural microbiome. Nevertheless, sterile pyuria remains a common and challenging condition to differentiate from a true urinary tract infection (UTI) in clinical practice. In addition to being a diagnostic challenge, definite guidelines regarding the management of sterile pyuria have not been established, contributing to the prevalence of inappropriate treatment of this condition.