Comparative Study of the Immunological Marker IL-6 and the Non-Immunological Marker PCT in Surgery Patients with Infections and Multiple Trauma

The objective of this study was to assess and to compare the time course of the immunological signaling marker IL-6 and the non-immunological marker PCT in surgical patients with local and systemic bacterial infections and with multiple trauma of well-defined severity. 45 surgical and 26 intensive care patients were enrolled in this collaborative study. We analyzed IL-6 and PCT blood concentrations under the different experimental conditions with Cochran's Q -criterion for testing null hypotheses. For the surgical patients with local infections and with systemic infections, we did not find a significant decline of IL-6 in the time course at the confidence intervals 0.999, 0.990, and 0.950. No differences in PCT concentrations were found for the various experimental conditions. The time course of IL-6 did not change significantly with medium and high severity trauma, whereas PCT declined over time with significance levels 0.990 and 0.950. The measurement of IL-6 is predominantly a research tool at present. There are no absolute indications for routine measurements. Regarding PCT, our results do not point to this marker as a valid predictor of bacterial infections including sepsis during the early period after trauma.