Can plasma-free DNA concentration be a diagnostic tool in critically ill septic patients?

Aim: To investigate the diagnostic value of plasma-free DNA concentration (PF-DNA) in septic patients compared to nonseptic patients and to correlate it with clinical outcome.Materials and methods: Forty-two mechanically ventilated consecutive patients (11 septic, 31 nonseptic) admitted to the intensive care unit (ICU) were recruited. On admission, besides PF-DNA concentration, APACHE II and SOFA scores and serum C-reactive protein (CRP), procalcitonin (PCT), and serum lipid concentrations, together with clinical outcome, were assessed. Plasma samples from 11 volunteers were also collected. Appropriate statistics were used for analysis.Results: Median PF-DNA concentrations on admission were significantly higher in septic patients compared to nonseptic patients [14,285 (48–180,311) GE/mL versus 546.5 (0–7674) GE/mL, P 0.0001]. For distinguishing septic and nonseptic patients on admission, the area under the curve obtained for PF-DNA concentration was 0.9 (sensitivity 84%, specificity 95%; cutoff 4083 GE/mL). There were no significant differences between PF-DNA concentrations of nonsurvivors and survivors. Additionally, DNA concentration demonstrated a significant correlation with CRP, PCT, and high-density lipoprotein concentrations.Conclusion: Plasma DNA seems to be a potentially valuable tool to confirm sepsis diagnosis upon ICU admission.