LAUSR

e19039 Background: In patients with lymphoma, lactate dehydrogenase (LDH) is an important prognostic marker. Serum lactate can also be elevated due to hypermetabolism from aggressive lymphoma. We have observed critically ill lymphoma patients with elevated serum lactate who had a delay in the diagnosis and treatment of their underlying lymphoma because the cause of the elevated lactate was presumed to be infection. This clinical observation led us to perform a study to evaluate the relationship between serum lactate and LDH levels in lymphoma patients. Methods: We used the Mayo Clinic Lymphoma Database to search for patients with lymphoma and elevated lactate during a recent two year time period, January 2014 through December 2015. Fifty patients met these initial criteria and underwent medical chart review. The patients were divided into two groups – those with documented infection (SepsisLA group) and those without infection (all cultures negative) where the elevated lactate was due to lymphoma hypermetabolism (LymLA group). The Wilcoxon/Kruskal-Wallis test was used to compare the SepsisLA and LymLA groups. Kaplan-Meier analysis was used to estimate survival. Results: The mean age of the 66 patients was 65 ± 14.8 years and 60% were male. At the time of presentation, the mean lactate and LDH values were 4.5 ± 2.81mmol/L (UNL < 2 mmol/L) and 835.1 ± 1741.4 U/L (UNL < 222 U/L), respectively. 64% (32/50) of patients had elevated LDH values. After review, 32 (64%) patients were in the SepsisLA group; 18 (36%) were in the LymLA group. DLBCL was the most common disease type in both the SepsisLA (50%; 16/32) and LymLA (88%; 16/18). The sepsisLA and LymLA groups were not significantly different in terms of age, sex, lactate levels, or maxSUV on PET scan (N = 13). However, patients in the LymLA group did have higher LDH values (p = 0.02) compared to those with SepsisLA. Patients with LymLA had a reduced overall survival (OS) (1.45 median months) compared to those with SepsisLA (7.83 median months) p = 0.02. Conclusions: This study demonstrates that the level of lactate elevation is not helpful indiscriminating SepsisLA vs LymLA; however an elevated LDH with elevated lactate is more likely LymLA. Lymphoma pts with LymLA had an inferior survival compared to SepsisLA. We are unable to define the true incidence and prognostic value of elevated serum lactate in lymphoma; this will require a prospective study with fresh samples. In summary, lymphoma activity can masquerade as infection with elevated lactate. Once sepsis is ruled out, treatment for the lymphoma should not be delayed as this presentation portends poor prognosis.