A case of extreme decrease in urinary creatinine level caused by urinary bacteria

Abstract

Analysis of urinary creatinine level is frequently used for the evaluation of general clinical conditions, which is especially useful for data corrections in urinalysis or the evaluation of renal function. A man in his sixties with advanced bladder cancer presented with an extremely low urinary creatinine level. Confirmatory tests ruled out technical errors and revealed that Prebotella loescheii and Anaerococcus tetradius degraded creatinine in the urine. Creatinine degradation depended on the amount of bacteria and temperature. Occasionally, urinary creatinine levels were also very low, which demonstrated that creatinine was degraded in his bladder. In addition, the urinary creatinine level decreased with increasing amount (10⁶–10⁷/μL) of the two bacteria. Therefore, attention should be paid to the potential negative error of urinary creatinine in bacteria-contaminated urine.