Role of Procalcitonin in Differentiating between Infectious and Noninfectious Fevers among Patients with Lymphoma

Objective The primary objective of this study is to prospectively evaluate the role of procalcitonin (PCT) in distinguishing infectious fever from noninfectious fever (NIF) among febrile lymphoma patients. The secondary objective is to evaluate the usefulness of PCT in distinguishing among bloodstream infections (BSI), local infections and unidentified infections (LIUI), and NIF. Methods Patients with lymphoma and fever were prospectively recruited between August 2014 and November 2015. PCT was measured within 24 hours of fever onset (PCT1) and 24-72 hours thereafter (PCT2). The higher PCT value between PCT1 and PCT2 was also documented (PCTmax ). PCT levels (PCT1, PCT2, and PCTmax ) were compared for BSI, LIUI, and NIF. In addition, the difference between PCT1 and PCT2 was evaluated in patients with complete data on both PCT1 and PCT2. Results Of 108 eligible patients, 12 were diagnosed with BSI, 83 with LIUI, and 13 with NIF. PCTmax was statistically different between the infectious fever (BSI and LIUI combined) and NIF groups (median PCTmax : 0.44 ng/ml vs 0.19 ng/ml; p=0.026). PCT1 was not statistically different for patients with BSI, LIUI, and NIF (p=0.217). However, PCT2 and PCTmax were significantly higher in patients with BSI compared to those with NIF (p=0.026 and 0.002, respectively). Meanwhile, patients with BSI have significantly higher PCTmax values than those with LIUI (p=0.034). Among 90 cases with complete data on both PCT1 and PCT2, PCT2 was significantly higher than PCT1 in patients with BSI (median PCT: 0.98 ng/ml vs 0.47 ng/ml; p=0.045) and patients with LIUI (median PCT: 0.43 ng/ml vs 0.24 ng/ml; p=0.004), while not significant in patients with NIF (p=0.374). Conclusion Two separate PCT measurements can differentiate between infectious fever and NIF and predict for BSI in lymphoma patients with fever.