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Early diagnostic and prognostic value of procalcitonin and interleukin 6 for catheter-related bloodstream infections in critically ill patients

SUI Ming-liang, WU Chang-jiang, HUANG Chao-fa, ZHU Tuan-jie   

  1. Department of Critical Care Medicine, Suzhou Kowloon Hospital, Shanghai Jiaotong University School of Medicine, Suzhou 215028, China
  • Online:2013-11-28 Published:2013-12-03


Objective To evaluate the early diagnostic and prognosis value of procalcitonin  (PCT), interleukin 6 (IL-6), and PCT kinetics for central venous catheter related bloodstream infections (CRBSI) in selected critically ill patients. Methods Thirty-six patients received central venous catheter, who were suspected of having CRBSI. All the patient blood samples were obtained for detection of PCT, IL-6 levels, and for blood culture on the first day, and catheter were also obtained for culture. PCT levels were measured on day 1, 2, 3, and 7 after infection. The patients were divided into CRBSI group and non-CRBSI group. The CRBSI group was divided into controlled infection group and non-controlled infection group, and PCT kinetics for prognostic value was observed. Results Fifteen patients were diagnosed as CRBIS (41.67%). Levels of PCT and IL-6 were significantly higher in patients with CRBIS than those without CRBIS on the first infection day (P<0.001 and P<0.005). The ROC curves indicated that the area under the curve (AUC) for PCT and IL-6 was 0.832 and 0.78, respectively. The cutoff points of PCT and IL-6 were set to be 4.3 μg/L and 464.5 ng/L for patients with proven CRBSI, respectively. The corresponding sensitivity, specificity, positive predictive value, and negative predictive value were 80.0% and 77.3%, 95.2% and 66.7%, 92.25% and 61.12%, and 86.95% and 77.76%, respectively. PCT serum levels tended to decrease in patients with controlled CRBSI, whereas in non-controlled patients was proven to remain stably in high level. Conclusion PCT and IL-6 might be valuable early diagnostic parameters for CRBIS with high specificity and negative predictive value, and PCT kinetics has certain predictive value for the prognosis of CRBSI.

Key words: critical illness, catheterization, central venous, catheter-related bloodstream infection, procalcitonin, interleukin 6