Abstract

Objectives: To describe the clinical and laboratory characteristics of patients with sepsis treated in the intensive care unit (ICU) and to evaluate the ability of initial blood lactate levels to predict in-hospital mortality.

Methods: We conducted a cross-sectional descriptive study of 100 patients with sepsis admitted to the ICU between January and July 2025, diagnosed according to Sepsis-3 criteria. Blood lactate was recorded within the first 24 hours after ICU admission. Lactate levels were compared between groups using the Mann–Whitney U test. Receiver operating characteristic (ROC) curve analysis was performed to assess the mortality prediction performance of lactate

Results: The mean age was 68.42±15.04 years; the prevalence of septic shock was 61% and overall mortality was 30%. The median admission lactate level was 4.5 (3.0–6.8) mmol/L, and 90% of patients had lactate ≥2 mmol/L. Lactate levels were significantly higher in non-survivors than in survivors (6.4 ± 3.9 vs. 4.7 ± 2.6 mmol/L; p=0.001). ROC analysis demonstrated limited discrimination for mortality (AUC=0.602; p=0.165). A cut-off value of 9.16 mmol/L yielded a specificity of 95% and a sensitivity of 36%..

Conclusions: Initial blood lactate levels are commonly elevated in patients with sepsis and are associated with mortality. However, the mortality prediction performance of a single lactate measurement is limited; therefore, lactate should be interpreted as a risk marker in the initial assessment and considered alongside clinical factors and severity scoring systems to support management decisions.