Objective:To investigate the prognostic value of early serum lactate, albumin, and lactate/albumin ratio (L/A) on the 28-day prognosis of adult patients with sepsis.Methods:A retrospective cohort study was conducted among adult patients with sepsis admitted to the First Affiliated Hospital of Xinjiang Medical University from January to December in 2020. Gender, age, comorbidities, lactate within 24 hours of admission, albumin, L/A, interleukin-6 (IL-6), procalcitonin (PCT), C-reactive protein (CRP) and 28-day prognosis were recorded. The receiver operator characteristic curve (ROC curve) was drawn to analyze the predictive value of lactate, albumin and L/A for 28-day mortality in patients with sepsis. Subgroup analysis of patients was performed according to the best cut-off value, Kaplan-Meier survival curves were drawn, and the 28-day cumulative survival of patients with sepsis was analyzed.Results:A total of 274 patients with sepsis were included, and 122 patients died at 28 days, with a 28-day mortality of 44.53%. Compared with the survival group, the age, the proportion of pulmonary infection, the proportion of shock, lactate, L/A and IL-6 in the death group were significantly increased, and albumin was significantly decreased [age (years): 65 (51, 79) vs. 57 (48, 73), pulmonary infection: 75.4% vs. 53.3%, shock: 37.7% vs. 15.1%, lactate (mmol/L): 4.76 (2.95, 9.23) vs. 2.21 (1.44, 3.19), L/A: 0.18 (0.10, 0.35) vs. 0.08 (0.05, 0.11), IL-6 (ng/L): 337.00 (97.73, 2 318.50) vs. 55.88 (25.26, 150.65), albumin (g/L): 27.68 (21.02, 33.03) vs. 29.62 (25.25, 34.23), all P < 0.05]. The area under the ROC curve (AUC) and 95% confidence interval (95% CI) of lactate, albumin, and L/A were 0.794 (95% CI was 0.741-0.840), 0.589 (95% CI was 0.528-0.647), 0.807 (95% CI was 0.755-0.852) for predicting 28-day mortality in sepsis patients. The optimal diagnostic cut-off value of lactate was 4.07 mmol/L, the sensitivity was 57.38%, the specificity was 92.76%. The optimal diagnostic cut-off value of albumin was 22.28 g/L, the sensitivity was 31.15%, the specificity was 92.76%. The optimal diagnostic cut-off of L/A was 0.16, the sensitivity was 54.92%, and the specificity was 95.39%. Subgroup analysis showed that the 28-day mortality of sepsis patients in the L/A > 0.16 group was significantly higher than that in the L/A ≤ 0.16 group [90.5% (67/74) vs. 27.5% (55/200), P < 0.001]. The 28-day mortality of sepsis patients in the albumin ≤ 22.28 g/L group was significantly higher than that in the albumin > 22.28 g/L group [77.6% (38/49) vs. 37.3% (84/225), P < 0.001]. The 28-day mortality in the group with lactate > 4.07 mmol/L was significantly higher than that in the group with lactate ≤ 4.07 mmol/L [86.4% (70/81) vs. 26.9% (52/193), P < 0.001]. The three were consistent with the analysis results of Kaplan-Meier survival curve. Conclusion:The early serum lactate, albumin, and L/A were all valuable in predicting the 28-day prognosis of patients with sepsis, and L/A was better than lactate and albumin.