febrile patients Usefulness of cell-free plasma DNA, procalcitonin and C-reactive protein as markers of infection in

Abstract Background: Circulating nucleic acids were discovered more than 60 y ago. With the recent developments in the study ofcirculating nucleic acids, its application in the diagnostic field has increased. The objective of this study was to assess theusefulness of the quantification of cell-free plasma DNA (CF-DNA) concentration in the diagnosis of infections in febrilepatients and as a prognostic marker in septic patients.Methods: Concentrations of CF-DNA, procalcitonin (PCT) and C-reactive protein (CRP) were measured in 110 febrile patientswho were clinically diagnosed with fever of unknown origin, localized infection, sepsis or septic shock.Results: Concentrations of CF-DNA increase according to the severity of the infection. The best cut-off point for predictinginfection was 2800 GE (genome equivalents)/mL (sensitivity: 95.0%; specificity: 96.7%) and 14,000 GE/mL for sepsisprediction (sensitivity: 77.8%; specificity: 94.6%). Higher concentrations of CF-DNA were found in exitus septic patients thanin survivors. The diagnostic efficiency of CF-DNA was similar to PCT and higher than CRP in infectious processes.Conclusions: Normal concentrations of CF-DNA can exclude the presence of an infection in febrile patients, and very highconcentrations (.10-fold over the normal reference range) stratify the severity of infections, showing a high prognostic valueto predict mortality in the absence of other causes for elevated CF-DNA.Ann Clin Biochem 2010; 47: 253–258. DOI: 10.1258/acb.2010.009173