title: Old and new biomarkers for predicting high and low risk microbial infection in critically ill patients with new onset fever: a case for procalcitonin.
abstract: OBJECTIVE
  Fever suggests the presence of microbial infection in critically ill patients. The aim was to compare the role of old and new biomarkers in predicting absence or presence of microbial infection, its invasiveness and severity in critically ill patients with new onset fever.
  
  
  METHODS
  We prospectively studied 101 patients in the intensive care unit with new onset fever (>38.3 °C). Routine infection parameters, lactate, procalcitonin (PCT), midregional pro-adrenomedullin (MR proADM), midregional pro-atrial natriuretic peptide (MR proANP) and copeptin (COP) were measured daily for three days after inclusion. Likelihood, invasiveness (by bloodstream infection, BSI) and severity of microbial infection were assessed by cultures, imaging techniques and clinical courses.
  
  
  RESULTS
  All patients had systemic inflammatory response syndrome; 45% had a probable or proven local infection and 12% a BSI, with 20 and 33% mortality in the ICU, respectively. Only peak PCT (cutoff 0.65 ng/mL at minimum) was of predictive value for all endpoints studied, i.e. BSI, septic shock and mortality (high risk infection) and infection without BSI, shock and mortality (low risk infection), at areas under the receiver operating characteristic curves varying between 0.67 (P = 0.003) and 0.72 (P < 0.001). In multivariable analysis, the combination of C-reactive protein and lactate best predicted high risk infection, followed by PCT. For low risk infection, PCT was the single best predictor.
  
  
  CONCLUSIONS
  In critically ill patients with new onset fever, plasma PCT as a single variable, among old and new biomarkers, best helps, to some extent, to predict ICU-acquired, high risk microbial infection when peaking above 0.65 ng/mL and low risk infection when peaking below 0.65 ng/mL.
authors.affiliation: Department of Intensive Care, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands. sandrahoeboer@hotmail.com
authors.forename: Sandra H
authors.initials: SH
authors.lastname: Hoeboer
authors.forename: Erna
authors.initials: E
authors.lastname: Alberts
authors.forename: Ingrid
authors.initials: I
authors.lastname: van den Hul
authors.forename: Annelies N
authors.initials: AN
authors.lastname: Tacx
authors.forename: Yvette J
authors.initials: YJ
authors.lastname: Debets-Ossenkopp
authors.forename: A B Johan
authors.initials: AB
authors.lastname: Groeneveld
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001424:Bacterial Infections / Q000175:diagnosis* / Q000401:mortality / Q000473:pathology; D015415:Biomarkers / Q000097:blood*; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D016638:Critical Illness; D005260:Female; D005335:Fever of Unknown Origin / Q000175:diagnosis* / Q000209:etiology* / Q000401:mortality / Q000473:pathology; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011498:Protein Precursors / Q000097:blood*; D018805:Sepsis / Q000175:diagnosis* / Q000401:mortality / Q000473:pathology; D016019:Survival Analysis; D018746:Systemic Inflammatory Response Syndrome / Q000175:diagnosis / Q000401:mortality / Q000473:pathology
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D015740:Calcitonin Gene-Related Peptide