Procalcitonin used as a marker of infection in the intensive care unit

Objective: To determine the Value of procalcitonin (ProCT) as a marker of i nfection in critically ill patients. Design: Prospective, observational study. Setting: Medicosurgical department of intensive care(31 beds). Patients: One hundred eleven infected and 79 noninfected patients. interventions: None. Measurements and Main Results: ProCT and C-reactive protein (CRP) concentra tions were monitored daily. The best cutoff values for ProCT and CRP were 0 .6 ng/mL and 7.9 mg/dL, respectively. Compared with CRP, ProCT had a lower sensitivity(67.6 vs. 71.8), specificity (61.3 vs. 66.6), and area under the receiver operating characteristic curve (0.66 vs. 0.78, p < .05). The comb ination of ProCT and CRP increased the specificity far infection to 82.3%. In the infected patients, plasma ProCT, but not CRP, Values were higher in nonsurvivors than in survivors. Infected patients with bacteremia had highe r ProCT concentrations than those without bacteremia, but similar CRP conce ntrations. ProCT levels were particularly high in septic shock patients. Conclusions: ProCT is not a better marker of infection than CRP in critical ly ill patients, but it can represent a useful adjunctive parameter to iden tify infection and is a useful marker of the severity of infection.