Value of procalcitonin in the etiological diagnosis of bloodstream infections / 中华急诊医学杂志

ABSTRACT

Objective:To evaluate the accuracy of serum concentration of procalcitonin (PCT) in differential diagnosis of the etiology of bloodstream infections (BSI).Methods:Patients hospitalized in ICU of China-Japan Friendship Hospital from January 2015 to June 2020 with BSI and with PCT test simultaneously when blood drawing for blood culture were enrolled. Sequential Organ Failure Assessment (SOFA) were calculated based on parameters on the day of blood culture. Difference of various indicators among different pathogen infections were compared. Receiver Operating Characteristic (ROC) Curve was used to analyze the value of PCT in differential diagnosis of BSI by different pathogens.Results:Among 1 456 patients with BSI,1 261 (86.6%) patients with monobacterial infection, 80 (5.5%) patients with candidiasis and 115 (7.9%) patients with mixed infection. The 28-day mortality was 24.5% (356/1 456) and the 60-day mortality was 30.6% (446/1456). Mortality of both 28-day and 60-day in the mixed group was significantly higher than that in the bacteriacemia group and candidemia group. PCT levels was significantly higher in patients with bacteremia caused by gram-negative bacteria (GNB) than that in gram-positive bacteria (GPB) infected bacteremia and candidemia {3.4 μg/L[95% confidence interval (95% CI) 0.7-17.0 μg/L] vs 1.3 μg/L (95% CI 0.4-7.3 μg/L); 3.4μg/L (95% CI was 0.7-17.0 μg/L) vs 1.1 μg/L (95% CI was 0.4-3.4 μg/L); P<0.01} . ROC curve analysis showed that ① the optimal cut-off value of PCT in differential diagnosis of monobacterial bacteremia and candidemia was 7.25 μg/L, with specificity of 90.0% and the area under the ROC curve (AUROC) was 0.612 (95% CI 0.533-0.691). When PCT value was greater than 0.51 μg/L, the sensitivity of diagnostic of bacteremia could reach 73.3%. ② the optimal cut-off value of PCT in differential diagnosis of bacteremia caused by GNB infection and candidemia was 7.32 μg/L, with specificity of 90.0% and AUROC was 0.695 (95% CI 0.614-0.776). When PCT value was greater than 0.51 μg/L, the sensitivity of diagnostic of bacteremia caused by GNB infection was 84.9%.③ the optimal cut-off value of PCT in differential diagnosis of bacteremia caused by GNB and GPB infection was 0.52 μg/L, with sensitivity of 84.9% and AUROC was 0.713 (95% CI 0.672-0.755). When PCT value was greater than 7.36 μg/L, the specificity of diagnostic of bacteremia caused by GNB infection could reach 80.1%. Conclusions:PCT can provide additional information about the possible etiology of patients with BSI, especially as high levels often indicate the possibility of GNB bacteremia.