Serum procalcitonin (PCT) levels have been proposed as a new discriminative marker for bacterial and fungal infections. We analysed the diagnostic relevance of PCT in febrile episodes of neutropenic adult patients after haematopoietic stem cell transplantation (HSCT). PCT was determined prospectively in 92 febrile episodes, classified according to the final diagnosis as: neutropenic fever of unknown origin (n = 51), microbiological (n = 26) or clinical (n = 5) documented infection and non-infectious febrile episodes (n = 10). On first day of fever, mean (+/- SD) PCT level was 0.3 ng/ml (0.2) in neutropenic fever of unknown origin, 0.5 ng/ml (0.7) in microbiologically confirmed infections, 0.2 ng/ml (0.2) in clinically documented infections and 1.7 (4.2) in non-infectious fever (P = not significant). Five days after the antibiotic therapy was started, fever persisted in 29 neutropenic episodes (32%). Cases that were eventually diagnosed with invasive aspergillosis had PCT values significantly higher [10.1 ng/ml (6.7)] than all remaining groups (P = 0.027; Kruskal-Wallis). Our analysis indicates that the PCT level on first day of fever did not facilitate the differential diagnosis of neutropenic febrile episode. However, when fever persisted for more than 5 d, PCT values > or = 3 ng/ml had a high sensitivity and specificity for the diagnosis of invasive aspergillosis.
Copyright 2004 Blackwell Publishing Ltd