Serum procalcitonin level in children with sepsis: clinical significance of its dynamic monitoring

Objective To research the diagnostic value of serum procalcitonin (PCT) for sepsis and bacterial infection in children, and evaluate the value of severity and prognosis evaluation by dynamic monitoring for PCT levels in children with sepsis. Methods Prospective study. From July 2011 to April 2012, 297 children in PICU were divided into sepsis group (n=125) and non-sepsis group (n=172). The sepsis group were divided into severe sepsis group and non-severe sepsis group, at same time, to be divided into bacterial sepsis group and non-bacterial sepsis group. The concentrations of serum PCT, C-reactive protein (CRP), WBC, neutrophil ratio in different time periods were obtained; the pediatric critical illness scores were conducted and sepsis related organ failure assessment were evaluated, the condition of prognosis was observed. Results The level of PCT in sepsis group and non-sepsis group were (21.31±18.27) ng/ml, (4.35±2.63) ng/ml, respectively. PCT of sepsis group was higher than that of non-sepsis group (t=4.744, P<0.01). The area under ROC curve of PCT, CRP and WBC in sepsis group were 0.737 (95%confidence interval: 0.633~0.840), 0.704 (95%confidence interval: 0.610~0.799), 0.666 (95%confidence interval: 0.554~0.778), respectively. When the level of PCT was 10 ng/ml, the diagnosis of severe sepsis had critical value, with sensitivity 80.2% and specificity 82.6%. We found that PCT rapidly increased at the early infection by dynamically observing PCT, CRP and WBC of sepsis group. Furthermore, when the infection was controlled after using the antibiotic for 5 days, PCT also quiekly came down. However, CRP, WBC remained high level after controlling the infection and they declined slower than PCT. The PCT level of the children in the dead group was significantly higher than that in the survival group. PCT showed negative correlation with pediatric critical illness score (r=-0.621, P<0.05), and positive correlation with sepsis related organ failure assessment (r=0.755, P<0.01). Conclusion PCT has important value for diagnosing severe sepsis and bacterial sepsis. Dynamic PCT monitoring is valuable in severity classification and prognosis assessment for critically ill children with sepsis, and provide guides for clinicians to adjust the antibiotic use in time. Key words: Sepsis; Procalcitonin; C-reactive protein