BACKGROUND: Sepsis is a life-threating cause in childhood ages. The recognition and treatment early are significant for decreasing mortality. Sepsis has many factors and various biomarkers function in the pathogenesis, the stress indicators oxidants increased and antioxidants decreased. The objective of our study was to investigate the levels of thiol disulfides with and without sepsis in a pediatric intensive care unit (PICU). MATERIALS AND METHODS: A cohort study was conducted between October 2022 and March 2023 at the PICU, comprising 64 with sepsis and 62 children without sepsis. Blood samples from sepsis and the control group were collected and centrifuged. Subsequently, the samples were stored at -80 °C until the day of the experiment. Once the requisite number of patients had been enrolled, the thiol-disulfide values in the collected samples were analysed in accordance with the ELISA kit method. RESULTS: The research parameters investigated, namely total oxidant status, plasma 8-OHdG, total-native thiol and native/total thiol percent ratio, were found to be considerably elevated in the sepsis group in comparison to the control (p <
0.05). Furthermore, the oxidative stress parameters investigated (total antioxidant status, paraoxonase 1 activity, disulfide, disulfide/native thiol percent ratio, disulfide/total thiol percent ratio) were found to be significantly lower in the sepsis group than in control (p <
0.05). CONCLUSIONS: In our study as well, we detected all antioxidant parameters are low and oxidant parameters are statistically significantly higher in sepsis. Our study posits that thiol-disulfide levels have the potential to serve as a diagnostic tool in conjunction with traditional established biomarkers of inflammation in critically ill children in the PICU who are being treated for sepsis. CLINICAL TRIAL REGISTRATION: Not applicable.