Discriminative power of inflammatory markers for prediction of tumor necrosis facter-alpha and interleukin-6 in ICU patients with systemic inflammatory response syndrome (SIRS) or sepsis at arbitrary time points

Objectives: To determine the correlations and predictive strength of surrog ate markers (body temperature, leukocyte count, C-reactive protein (CRP) an d procalcitonin (PCT)) with elevated levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in septic patients on randomly chosen days. Design: Prospective consecutive case series. Setting: Surgical intensive care unit (ICU) of a university hospital. Patients: Two hundred forty-three patients experiencing ICU stays of longer than 48 h categorized for sepsis according to ACCP/SCCM Consensus Conferen ce criteria. Measurements and main results: CRP and PCT were both significantly correlat ed with TNF-alpha and IL-6, Based on the area under the curve (AUC) of the receiver operating characteristic (ROC) curves, predictive capability was h ighest for PCT (0.846 for TNF-alpha > 40 pg/ml and 0.837 for IL-6 > 500 pg/ ml), moderate with CRP (0.744 and 0.748, respectively), and lowest for leuk ocyte count (0.562 and 0.534, respectively) and body temperature (0.570 and 0.623, respectively), Sensitivity, specificity, positive and negative pred ictive values and test effectiveness all followed this same pattern of bein g highest for PCT followed by CRP, with leukocyte count and body temperatur e being lowest. Conclusion: PCT may be an early and better marker of elevated cytokines tha n the more classic criteria of inflammation.