title: Clinical utility of procalcitonin as a marker of sepsis: a potential predictor of causative pathogens.
abstract: OBJECTIVE
  Sepsis is one of the leading causes of mortality in critically ill patients, and providing a timely diagnosis and early intervention is necessary for successful treatment. Procalcitonin (PCT) may be a better marker of sepsis than conventional inflammatory markers. The aim of this study was to evaluate the clinical utility of the PCT level as a marker of sepsis.
  
  
  METHODS
  Forty-five patients with sepsis, 24 patients with pneumonia who did not meet the SIRS criteria (PN) and 56 controls were enrolled in this study. The levels of PCT and other serum markers were measured, and their utility as markers of sepsis was assessed.
  
  
  RESULTS
  The serum PCT levels exhibited statistically significant differences between the three groups (p<0.0001). The PCT levels in the sepsis group (29.3 ± 85.3 ng/mL) were significantly higher (p<0.001) than those observed in the PN group (0.34 ± 8.6 ng/mL) and the control group (0.74 ± 2.1 ng/mL), according to a post hoc analysis. There were no differences in the white blood cell (WBC) counts or C-reactive protein (CRP) levels between the three groups. Fourteen of the 45 patients with sepsis had positive microbiological blood cultures (Gram-positive cocci [GPC] in seven patients, Gram-negative rods [GNR] in six patients, other types of bacteria in one patient). The 13 patients with GNR or GPC were categorized into the GNR group or GPC group according to the identified pathogens. The serum PCT levels were significantly higher in the GNR group (149.8 ± 199.7 ng/mL) than in the GPC group (19.1 ± 41.8 ng/mL) (p<0.05), although there were no differences in the WBC counts or CRP levels between these groups. When the cut-off value for the PCT level was set at 16.9 ng/mL, the sensitivity and specificity for the detection of GNR infection were 85.7% and 83.3%, respectively.
  
  
  CONCLUSIONS
  The PCT level is a potentially useful marker of the type of causative pathogen in patients with sepsis whose measurement may facilitate the selection of appropriate empiric antibiotic treatment.
authors.affiliation: Department of Laboratory Medicine, Dokkyo Medical University Koshigaya Hospital, Japan.
authors.forename: Atsuko
authors.initials: A
authors.lastname: Nakajima
authors.forename: Junko
authors.initials: J
authors.lastname: Yazawa
authors.forename: Daisuke
authors.initials: D
authors.lastname: Sugiki
authors.forename: Mari
authors.initials: M
authors.lastname: Mizuguchi
authors.forename: Hironori
authors.initials: H
authors.lastname: Sagara
authors.forename: Masahiro
authors.initials: M
authors.lastname: Fujisiro
authors.forename: Mitsuei
authors.initials: M
authors.lastname: Shibazaki
authors.forename: Akihiko
authors.initials: A
authors.lastname: Hitani
authors.forename: Masako
authors.initials: M
authors.lastname: To
authors.forename: Kosuke
authors.initials: K
authors.lastname: Haruki
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006090:Gram-Negative Bacteria / Q000302:isolation & purification; D016905:Gram-Negative Bacterial Infections / Q000097:blood* / Q000175:diagnosis / Q000382:microbiology; D016908:Gram-Positive Bacterial Infections / Q000097:blood* / Q000175:diagnosis / Q000382:microbiology; D006095:Gram-Positive Cocci / Q000302:isolation & purification; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011498:Protein Precursors / Q000097:blood*; D012372:ROC Curve; D015203:Reproducibility of Results; D018805:Sepsis / Q000097:blood* / Q000175:diagnosis / Q000382:microbiology
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide