Value of evaluating procalcitonin kinetics in diagnosis of infections in patients undergoing laparoscopic radical cystectomy

Postsurgery infection is a common complication after laparoscopic radical cystectomy (LRC) followed by urinary diversion. White blood cell (WBC) values and C-reactive protein (CRP) are routinely used as markers for infection, but lack of specificity and their elevation is often delayed in clinically significant events. In this study, we aimed to investigate the value of procalcitonin (PCT) kinetics in assisting early diagnosis of infection in patients undergoing LRC. The patients’ medical records between May 2013 and May 2016 were reviewed retrospectively. WBC, CRP, and PCT plasma levels as well as clinical symptoms were registered in 306 patients preoperatively (day 0), and 5 consecutive days postoperatively. Based on microbiological and clinical data, patients were grouped into noninfection- (NI-) and infection- (I-) groups. The day of new onset infection was observed were defined as day t0 and the day after that as day t1. For the NI-group, the day on which PCT was at the peak was defined as day t1 and the previous day as day t0. Of the 306 patients, 46 (15.03%) have proven infection. PCT levels were analogous at day t0:NI-group [median (interquartile range)]: 0.69(1.99) vs I-group [median (interquartile range)]: 1.0[0.75], P = .1. PCT levels were significantly increased at day t1 in the I-group[median (interquartile range)]:2.9(1.3) vs NI-group[median (interquartile range)]: 1.3(1.5), P < .01. The area under the curve for the prediction of infection was 0.72 [95% confidence interval (CI) = 0.63–0.81] for the absolute value of PCT; and for delta PCT:0.88 (95% CI = 0.81–0.94), P < .01. The optimal cut-off value was 0.79 ng/mL with the highest Youden index of 0.80 for delta-PCT to indicate infection. Neither absolute values nor changes in CRP, or WBC could predict infection better. The “delta” was considered as the changes in the absolute values (subtracting day t0 from day t1) of PCT, CRP, and WBC. This study suggest that early elevation of PCT within the first 24 hours of new onset infection, interpreted with clinical results, appears to be a promising indicator for the diagnosis of infections following LRC.