title: Prospective study on procalcitonin and other systemic infection markers in patients with leukocytosis.
abstract: OBJECTIVE
  To better assess the diagnosis of an infection in patients presenting at an emergency department with peripheral blood leukocytosis (>10 x 10(9) cells/l) on laboratory testing.
  
  
  METHODS
  We prospectively evaluated serum procalcitonin concentration (PCT), C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR). Patients were divided into two groups according to their final diagnosis: patients with infection and those without infection. PCT, CRP, and ESR were compared between these groups. Sensitivity, specificity, positive predictive values, negative predictive values, receiver operating characteristic curves, and areas under the curves were calculated for each biological measurement.
  
  
  RESULTS
  Out of 173 patients, 99 (57%) had a final diagnosis of systemic infection. If a cutoff point of 0.5 ng/ml is considered, procalcitonin concentration had a sensitivity of 0.57, a specificity of 0.85, a negative predictive value of 0.59, and a positive predictive value of 0.84 for the diagnosis of a systemic infection. Adding CRP or ESR to PCT gave no more information (p=0.84).
  
  
  CONCLUSIONS
  Only about half of the patients attending the emergency department with leukocytosis were suffering from an infection. Determination of the procalcitonin level may be useful for these patients, particularly in the case of a value higher than 0.5 ng/ml.
authors: Département de médecine interne, Hôpital de la ville, rue du Chasseral 20, 2300 La Chaux-de-Fonds, Switzerland.
authors: Pamela
authors: P
authors: Indino
authors: Pierre
authors: P
authors: Lemarchand
authors: Pierre
authors: P
authors: Bady
authors: Antoine
authors: A
authors: de Torrenté
authors: Louis
authors: L
authors: Genné
authors: Daniel
authors: D
authors: Genné
mesh_terms: D000368:Aged; D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood*; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000032:analysis; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D005260:Female; D006801:Humans; D007239:Infections / Q000175:diagnosis*; D007964:Leukocytosis / Q000175:diagnosis* / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011498:Protein Precursors / Q000097:blood*; D012372:ROC Curve; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide