[Procalcitonin in pyelonephritis and acute community-acquired pneumonia in adults].

OBJECTIVES: Procalcitonin (PCT) is an acute-phase protein involved in the specific inflammatory reaction to severe bacterial or fungal infections. This protein does however lack sensitivity in focal infections.

PATIENTS AND METHODS: In this study, we investigated PCT, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), leukocytosis, and fibrinogen levels at admission among adult patients hospitalized for community-acquired pneumonia (n = 33) or pyelonephritis (n = 30) and in a control population (n = 27) of patients with viral infections and non-infectious inflammatory diseases.

RESULTS: Median serum PCT in the control group (0.21 ng/ml) was significantly lower than in the pyelonephritis group (0.46 ng/ml, p < 0.0005) or the pneumonia group (0.88 ng/ml, p < 0.0005). In the control group, median CRP was 51.4 ng/l reaching 220 mg/l in the pyelonephritis and 198 mg/l in the pneumonia group (p < 0.0005 in both cases). The other markers of inflammation investigated (leukocytosis, ESR, fibrinogen) did not show such differences between the control group and the sepsis groups. The sensitivity of PCT (threshold 0.5 ng/ml) was 61% for the diagnosis of pneumonia and 44% for the diagnosis of pyelonephritis. Specificity was 92% in both cases. In comparison, the sensitivity of CRP (threshold 50 mg/l) was 94% and 91% for pyelonephritis and pneumonia respectively with a 33% specificity in both cases.

CONCLUSION: PCT is a specific but poorly sensitive marker of community-acquired pneumonia and pyelonephritis among adults hospitalized in medical wards.