Diagnostic and prognostic values of admission procalcitonin levels in community-acquired pneumonia in an intensive care unit.

BACKGROUND: Measurement of procalcitonin (PCT) has been studied for several years in infectious diseases. Some studies have focused on community-acquired pneumonia (CAP) but only one was conducted in critically ill patients hospitalized in an intensive care unit (ICU). PATIENTS AND METHODS: To determine the diagnostic and prognostic role of PCT in patients admitted in an intensive care unit for severe CAP, 110 patients hospitalized in our unit were prospectively studied. Within 48 hours following ICU admission, PCT serum level was measured with a quantitative method above a threshold value of 0.5 ng/ml.
RESULTS: Initially focusing on the diagnostic value of PCT, 20% of the patients had a serum PCT level <0.5 ng/ml, 30% between 0.5 ng/ml and 2 ng/ml, and 50%>/=2 ng/ml. Serum PCT level was higher in microbiologically documented CAP (median=4.9 ng/ml vs 1.5 ng/ml if no bacteria were found; p=0.001), but was not predictive of any specific bacterial agent. Concerning the prognostic value, the serum PCT level was higher for bacteremic patients and/or septic shock patients (4.9 ng/ml vs 1.5 ng/ml; p=0.0003). Moreover, PCT levels were increased in patients who developed, during their ICU stay, infection-related complications (septic shock, multiorgan dysfunction, acute respiratory distress syndrome and disseminated intravascular coagulation). Finally, the initial PCT level was significantly higher in patients who died during the ICU stay (5.6 ng/ml vs 1.5 ng/ml; p<0.0001). Such a relationship was not found with C-reactive protein (CRP).
CONCLUSION: In ICU patients admitted for severe CAP, initial PCT values could be an interesting predictor for complications and mortality.