Introduction: Procalcitonin (PCT) has been proposed as a marker of infection in critically ill patients. The aim of the study was to evaluate and compare the possible discriminative use of PCT together with other standard inflammatory parameters, such as C-reactive protein (CRP), platelets (PLT), white blood cell count (WBC) and immature granulocytes (IG) in differentiating systemic and localized bacterial infection in critically ill patients.
Materials and methods: According to clinical sings and microbiologic findings, 25 patients were divided into two groups: group A - patients with systemic bacterial infection and group B - patients with localized bacterial infection. Concentration of PCT and CRP; PLT, WBC and IG count were determined in all patients.
Results: The median concentration of PCT was 1.3 (range: 0.1-7.4) μg/L in group A and 0.2 (range: 0.1-9.1) μg/L in group B with differences between groups being statistically significant (P = 0.038). A significantly higher median PLT count (P = 0.012) was found in group B (327, range: 91-647 x 109/L) as compared to group A (140, range: 40-325 x 109/L). In contrast, there were no statistically significant differences in median values of CRP, WBC and IG between groups (P = 0.071; 0.189 and 0.239, respectively). According to ROC (receiver operating characteristic) analysis, the obtained cut-off value for PCT as the marker of systemic bacterial infection was 0.3 μg/L (sensitivity 91%, specificity 64%).
Conclusion: According to our results, PCT concentrations and PLT counts showed better discrimination than other investigated standard inflammatory parameters for differentiating systemic from localized bacterial infection in critically ill patients
