Procalcitonin:: a useful discriminator between febrile conditions of different origin in hemato-oncological patients?

Plasma concentrations of procalcitonin (PCT) have been shown to be elevated in bacterial and fungal infections. In contrast to C-reactive protein (CRP), PCT is not elevated in inflammations of noninfectious origin. Febrile inflammatory conditions are frequent in patients with hemato-oncological diseases. A reliable marker to discriminate infectious inflammations from drug-related and tumor-associated fever is still lacking. To evaluate the impact of PCT in this setting, PCT and CRP were prospectively measured in 95 febrile hemato-oncological patients. Infections could be identified in 40 of 95 patients: 38 of 95 had fever of unknown origin (FUO), 9 patients were suspected to suffer from drug-related fever, and 8 patients from tumor-associated fever. In the noninfection group (drug-related and tumor-associated fever), PCT levels were significantly lower than in patients with infections (P<0.001) or FUO (P<0.001). Differences were still highly significant comparing patients with suspected drug-related or tumor-associated fever alone with the infection or the FUO cohort. All eight patients with tumor-associated fever as well as eight of the nine patients with drug-related fever had PCT levels within the normal range (<0.5 mu g/l). CRP values only partially allowed discrimination between the various subgroups. Differences were significant between patients with drug-related fever and the infection (P=0.001) or FUO group (P=0.004). However, as CRP levels were far above the normal range also in the patients with drug-related fever, the significance of individual values was rather limited. In conclusion, PCT may provide useful additional information to assess the clinical significance of febrile conditions. PCT may facilitate the decision on when to initiate antimicrobial or cytotoxic therapy.