The utility of procalcitonin in febrile neutropenia.

12040 Background: The utility of procalcitonin (PCT) in febrile neutropenia (FN) in oncology patients on active therapy has not been well validated. FN constitutes a critical oncologic emergency, often characterized by subtle manifestations of infection, and timely diagnosis and treatment is vital. Although a potential harbinger of dangerous infection, FN can also occur without an identifiable infection, in which case hospitalization and antibiotics may be unnecessary. PCT, an amino acid, is elevated specifically during bacterial infections in the non-cancer population and correlates with infection severity. Clinicians employ PCT levels as a diagnostic adjunct, discerning bacterial from viral infections and analyzing PCT changes to guide treatment decisions. We examined oncology patients presenting with FN to correlate PCT levels and trends with confirmed infections. Methods: We identified patients with neutropenic fever, cancer, and a PCT result seen at our institution from 12/1/2017-12/1/2022. Patients were determined to have a confirmed infection if they had a positive bacterial blood culture. Demographics and clinical characteristics were compared between infection status and induction chemotherapy or transplant status using a Wilcoxon Rank Sum test for continuous variables and a Chi-Square or Fisher’s Exact test for categorical variables. Baseline (at time of initial FN) and highest PCT levels were compared by patient and disease characteristics and proven infection using Wilcoxon Rank Sum test. Logistic regression was used to determine the association of log-transformed PCT (baseline and highest) with proven infection (yes/no) while adjusting for covariates. All tests were two-tailed with p< 0.05 considered statistically significant. Results: Of 365 patients, 61 (16.7%) had an identified infection. Median baseline and peak PCT of 1.26 and 1.51 ng/mL, respectively, were significantly greater for these patients as compared to those with negative cultures at 0.54 and 0.65 ng/mL, respectively (P= 0.01 and <0.01). For every unit increase in the log transformed baseline PCT, the odds of having a proven infection increased by 23%. There were no significant differences in patient or clinical characteristics between those with and without infection. Of those admitted for induction chemotherapy and transplant who developed FN, PCT at time of initial fever was higher at 0.97 vs 0.56 ng/mL (p=0.02). Interestingly, median baseline and median peak PCT differed between gender with females 0.51 and males 0.72 ng/mL (p=0.02) at baseline, and 0.63 vs 0.83 ng/mL (p=0.04), respectively, at peak. Conclusions: PCT levels in cancer patients with FN are significantly associated with culture positive infection. This data can help guide treatment and de-escalation of antibiotics in cancer patients admitted with FN. Further evaluation should be taken to determine how to best use PCT to determine the need for admission and antibiotic prescription.