[Diagnostic value of serum procalcitonin in urinary tract infection]

To analyze the serum level of procalcitonin (PCT) in urinary tract infection (UTI) patients with urinary obstruction or bacteremia, and to investigate the value of PCT in diagnosing UTI.

A total of 102 patients with UTI hospitalized from January to December 2013 in the Second Hospital of Tianjin Medical University were categorized into obstructed UTI (n=60) and non-obstructed UTI (n=42), whose serum PCT concentrations were compared. Blood cultures were implemented in 44 patients, including 13 with positive findings (bacteremia) and 31 with negative findings (non-bacteremia). Serum PCT levels were also compared between the bacteremia and non-bacteremia groups. Receiver operating characteristic (ROC) curves were constructed to illustrate the performance of PCT in diagnosing urinary obstruction and bacteremia.

The median serum concentration of PCT in the obstructed UTI group (1.71 (0.10-53.20) mg/L)was higher than that in the non-obstructed UTI group (0.21 (0.10-10.00) mg/L, P<0.001); the serum concentration of PCT in the bacteremia group (2.73 (0.10-41.60) mg/L) was higher than that in the non-bacteremia group (0.42 (0.10-53.20) mg/L, P=0.030). The area under ROC curve of PCT in diagnosing urinary obstruction and bacteremia was 0.80 (95% CI 0.71-0.89) and 0.71 (95% CI 0.53-0.88). The maximum negative predictive value (NPV) was 0.90 and 0.87, respectively, when the serum concentrations of PCT diagnosing bacteremia and urinary obstruction was 0.51 mg/L and 0.35 mg/L.

PCT may be of some value in diagnosing UTI with urinary obstruction or bacteremia.