206. The Utility of Lactate as a Biomarker for Sepsis in Cancer Patients

BACKGROUND: Serum lactate is included in the initial assessment of patients with sepsis. However, cancer patients develop lactic acidosis for a variety of reasons and are underrepresented in most studies. Therefore, elevated lactate levels may lead to overdiagnosis of sepsis and excessive antibiotic use. The purpose of this study is to evaluate the utility of lactate as a biomarker for sepsis in cancer patients. The primary endpoint is the rate of 24-hour lactate clearance between infectious and non-infectious causes of lactic acidosis in cancer patients. Secondary objectives explore the duration of antibiotic therapy (DOT), the impact of liver metastasis on serum lactate levels, and the role of procalcitonin in distinguishing between infectious and non-infectious causes of lactic acidosis. METHODS: Retrospective chart review by Antimicrobial Stewardship team Figure 1: Study design [Image: see text] RESULTS: Preliminary data from a random subset of our sample (45/150) suggests there is no difference in mean serum lactate levels between infectious and non-infectious groups (4.6 vs 6.4). However, a substantial difference exists in the rate of 24h lactate clearance, although the difference was not statistically significant (58.3% vs 33%; p=0.13) (Fig2). There was a significant difference in antibiotic DOT (12.6 vs 3.3; p< 0.0001) presumably due to robust antimicrobial stewardship practices. Consistent with previous studies, there was a significant difference in procalcitonin levels between groups (27.2 vs 1.5, p=0.04). A sub-analysis of non-infectious patients with liver metastasis revealed a statistically significant difference in the rate of lactate clearance (21% vs 61.5%, p=0.03) (Fig3) suggesting that liver involvement impacts lactate clearance. Antibiotic DOT were also longer in non-infectious patients with liver metastasis (4.53 vs 1.38, p=0.02). Comparing end points between cancer patients with and witthout infection. [Image: see text] Liver involvement affecting Lactate clearance in patients without infection. [Image: see text] CONCLUSION: Cancer patients often manifest SIRS criteria at baseline which may lead to the overdiagnosis of infection and excessive antibiotic usage. Our observation is that lactate clearance as opposed to degree of lactic acidosis may be a more accurate indicator of infection in cancer patients especially those with liver involvement. This information may mitigate unnecessary antibiotic use in cancer patients with persistent lactic acidosis unrelated to infection. DISCLOSURES: All Authors: No reported disclosures