Sensitivity and specificity of various markers of inflammation for the prediction of tumor necrosis factor-alpha and interleukin-6 in patients with sepsis

Objectives: To determine correlations and predictive strength of surrogate markers (body temperature, leukocyte count, C-reactive protein [CRP], and p rocalcitonin [PCT]) with elevated levels of tumor necrosis factor-alpha (TN F-alpha) and interleukin-6 (IL-6) in septic patients. Design: Prospective consecutive case series. Setting: Surgical intensive care unit (ICU) of a university hospital, Patients: A total of 175 patients experiencing intensive care unit stays >4 8 hrs categorized for sepsis according to ACCP/SCCM Consensus Conference cr iteria. 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 of the receiv er operating characteristics curves, predicting capability was highest for PCT (0.814 for TNF-alpha >40 pg/mL and 0.794 for IL-6 >500 pg/mL), moderate with CRP (0.732 and 0.716, respectively), and lowest for leukocyte count ( 0.493 and 0.483, respectively) and body temperature (0.587 and 0.589, respe ctively). Sensitivity, specificity, positive, and negative predictive value s and test effectiveness all followed this same pattern of being highest fo r PCT followed by CRP, with leukocyte count and body temperature being lowe st. Conclusion: PCT may be an early and better marker of elevated cytokines tha n the more classic criteria of inflammation.