Serum procalcitonin for the early recognition of nosocomial infection in the critically ill patients: a preliminary report.
BACKGROUND
The usefulness of procalcitonin (PCT) measurement in critically ill medical patients with suspected nosocomial infection is unclear. The aim of the study was to assess PCT value for the early diagnosis of bacterial nosocomial infection in selected critically ill patients.


METHODS
An observational cohort study in a 15-bed intensive care unit was performed. Seventy patients with either proven (n = 47) or clinically suspected but not confirmed (n = 23) nosocomial infection were included. Procalcitonin measurements were obtained the day when the infection was suspected (D0) and at least one time within the 3 previous days (D-3 to D0). Patients with proven infection were compared to those without. The diagnostic value of PCT on D0 was determined through the construction of the corresponding receiver operating characteristic (ROC) curve. In addition, the predictive value of PCT variations preceding the clinical suspicion of infection was assessed.


RESULTS
PCT on D0 was the best predictor of proven infection in this population of ICU patients with a clinical suspicion of infection (AUROCC = 0.80; 95% CI, 0.68-0.91). Thus, a cut-off value of 0.44 ng/mL provides sensitivity and specificity of 65.2% and 83.0%, respectively. Procalcitonin variation between D-1 and D0 was calculated in 45 patients and was also found to be predictive of nosocomial infection (AUROCC = 0.89; 95% CI, 0.79-0.98) with a 100% positive predictive value if the +0.26 ng/mL threshold value was applied. Comparable results were obtained when PCT variation between D-2 and D0, or D-3 and D0 were considered. In contrast, CRP elevation, leukocyte count and fever had a poor predictive value in our population.


CONCLUSIONS
PCT monitoring could be helpful in the early diagnosis of nosocomial infection in the ICU. Both absolute values and variations should be considered and evaluated in further studies.
Charles
Pierre Emmanuel
PE
Service de Réanimation Médicale, Hôpital Le Bocage, CHU de DIJON, France. pierre-emmanuel.charles@chu-dijon.fr
Kus
Emmanuel
E
Aho
Serge
S
Prin
Sébastien
S
Doise
Jean-Marc
JM
Olsson
Nils-Olivier
NO
Blettery
Bernard
B
Quenot
Jean-Pierre
JP
D000368:Aged; D015415:Biomarkers / Q000097:blood; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D016638:Critical Illness; D003428:Cross Infection / Q000097:blood / Q000175:diagnosis*; D042241:Early Diagnosis; D005260:Female; D006784:Hospitals, Teaching; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D053717:Pneumonia, Ventilator-Associated / Q000097:blood; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011498:Protein Precursors / Q000097:blood*; D012372:ROC Curve
D015415:Biomarkers; C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D015740:Calcitonin Gene-Related Peptide