Procalcitonin concentrations in patients with neutropenic fever.

To assess the usefulness of markers of inflammation in distinguishing bacterial infection from severe systemic nonbacterial inflammation, concentrations of procalcitonin, neopterin, endotoxin, tumor necrosis factor, and interleukin-6 were measured in 28 neutropenic patients at the onset of fever and twice thereafter at 4 h intervals. Infection was found in 11 patients, and 17 patients had fever of undetermined origin. The procalcitonin concentration increased rapidly in patients with infection: the response was detectable within 8 h of the onset of fever. Procalcitonin is a specific but not a sensitive marker of infection in patients with neutropenic fever. Its poor sensitivity was related to an absent or delayed response in patients with gram-positive infections. Considerable overlap between infected and noninfected patients was found in levels of endotoxin, tumor necrosis factor, and interleukin-6.