title: Usefulness of cell-free plasma DNA, procalcitonin and C-reactive protein as markers of infection in febrile patients.
abstract: BACKGROUND
  Circulating nucleic acids were discovered more than 60 y ago. With the recent developments in the study of circulating nucleic acids, its application in the diagnostic field has increased. The objective of this study was to assess the usefulness of the quantification of cell-free plasma DNA (CF-DNA) concentration in the diagnosis of infections in febrile patients 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 patients who 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 predicting infection was 2800 GE (genome equivalents)/mL (sensitivity: 95.0%; specificity: 96.7%) and 14,000 GE/mL for sepsis prediction (sensitivity: 77.8%; specificity: 94.6%). Higher concentrations of CF-DNA were found in exitus septic patients than in 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 high concentrations (>10-fold over the normal reference range) stratify the severity of infections, showing a high prognostic value to predict mortality in the absence of other causes for elevated CF-DNA.
authors.affiliation: Servicio de Bioquímica Clínica, Hospital Universitario Central de Asturias, Oviedo 33006, Spain.
authors.forename: Vanessa García
authors.initials: VG
authors.lastname: Moreira
authors.forename: Belén
authors.initials: B
authors.lastname: Prieto
authors.forename: Julia San Martín
authors.initials: JS
authors.lastname: Rodríguez
authors.forename: Francisco V
authors.initials: FV
authors.lastname: Alvarez
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood*; D002097:C-Reactive Protein / Q000032:analysis*; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D004247:DNA / Q000097:blood*; D005260:Female; D005335:Fever of Unknown Origin / Q000097:blood / Q000175:diagnosis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011498:Protein Precursors / Q000097:blood*; D003294:Seizures, Febrile / Q000097:blood*; D018805:Sepsis / Q000097:blood / Q000175:diagnosis; D012772:Shock, Septic / Q000097:blood / Q000175:diagnosis; D055815:Young Adult
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D004247:DNA; D015740:Calcitonin Gene-Related Peptide