The role of procalcitonin in Emergency Medicine

Background:Pocalcitonin (PCT) could guide antibiotic therapy andevaluate its efficacy. Informations regarding the diagnostic andprognostic role of PCT in the critically ill subject are lacking. Aim ofthis study was to evaluate the value of PCT in the diagnosis ofbacterial infections and its prognostic weight in the unstable patient.Methods:We enrolled 1063 consecutive, critically ill subjectstreated in our Emergency Medicine Department in the period2008-2010, evaluating age, sex, haemodynamic parameters,leucocytes, troponin (TnI), creatinine and PCT and blood cultures.Results:We observed positive cultures in 375 subjects, whosemean PCT levels were significantly higher than in patients withoutpositive cultures (0.80ng/mlversus0.20ng/ml; p<0.05). ROCcurve analysis, however, underlined a sub-optimal value of PCT inpredicting a bacterial isolation (AUC: 0.58;95% CI:0.54-0.62).172 patients died, and their mean PCT values were significantlyhigher than survivors (2.62ng/mlversus0.17ng/ml;p<0.05).Calculating an optimal cutoff of 0.50ng/ml, mean time withoutevents among subjects with low PCT was 44 days, compared with26 days observed in patients with high PCT. The prognostic weightof PCT was superior than TnI, and PCT was correlated withprognosis independently from bacterial infection.Conclusions:Among critically ill patients PCT loses its diagnosticyeld. PCT maintains a good prognostic significance in predictingadverse events during the hospitalization particularly whenadopted in a model including clinical parameters (age andhaemodynamic values)