Dynamics of procalcitonin and bacteremia in neutropenic adults with acute myeloid leukemia.

Sensitive markers of infection are rare or of limited validity in neutropenic patients. Procalcitonin (PCT), a precursor protein of calcitonin, is a specific and sensitive marker of severe bacterial infections during short-term neutropenia. Because the value of PCT measurements among patients undergoing long periods of neutropenia remains uncertain and because several mechanisms, such as bacterial or fungal infections, reactions to drugs or blood products or tumor-associated events, can cause fever, we described the dynamics of PCT in 29 acute myeloid leukemia (AML) patients with 39 instances of chemotherapy-induced neutropenia. Plasma levels of PCT were determined prospectively by an immunoluminometric assay every four days starting at the onset of chemotherapy and continuing until the resolution of fever. We found that bacteremia did increase PCT levels above 0.5ng/mL and these levels predicted bacteremia at day 15 of chemotherapy. This finding may be relevant in the decision to alter antibiotic regimens to decrease toxicity and cost when patients remain febrile at day 15.