Plasma concentration monitoring is crucial for optimizing vancomycin use, particularly in patients in the intensive care unit (ICU). However, the reference interval for vancomycin plasma concentration remains undetermined.To evaluate the correlations of area under the curve (AUC0-24) and trough concentration (Cmin) with efficacy and nephrotoxicity in patients in the ICU.A total of 103 patients treated with vancomycin for methicillin-resistant Staphylococcus aureus infections were analyzed in this study. The associations of clinicodemographic characteristics (including sex, age, weight, infection sites, main etiologies of ICU cases, comorbidities, acute physiological chronic health evaluation II score, and mechanical ventilation) and pharmacokinetics (daily dose, Cmin, AUC0-24, and AUC0-24/minimum inhibitory concentration) with efficacy and nephrotoxicity of vancomycin were evaluated with univariate and multivariate logistic regression analyses. AUC0-24 was calculated using VCM-TDM software based on vancomycin population pharmacokinetics and Bayesian feedback method.Cmin over 9.4 μg/mL and AUC0-24 exceeding 359.6 μg × hour/mL indicated good efficacy against infection. Cmin below 14.0 μg/mL predicted no significant nephrotoxicity.In this study, the effective and safe concentration interval for vancomycin in patients in the ICU was Cmin 9.4-14.0 μg/mL. Close attention should be paid to adverse effects and renal function during vancomycin treatment.©The Author(s) 2025. Published by Baishideng Publishing Group Inc. All rights reserved.