BACKGROUND The aim of this study was to find a simple and easily accessible scoring system that could predict the development of sepsis in the preseptic period. MATERIAL AND METHODS The study included 161 patients with a basal sequential organ failure assessment (SOFA) value of 2 or more. The sepsis group (n=83) comprised patients with infection reported in culture results; the control group (n=78) comprised patients not showing evidence of infection in blood, urine, and phlegm cultures; samples were taken on three consecutive days. RESULTS The patients in both groups were divided into subgroups of non-survivor and survivor patients. The preseptic and septic SOFA score, neutrophil lymphocyte ratio (NLR), and procalcitonin (PRC) and lactate (Lac) values were determined to be statistically significantly higher in the sepsis group than in the control group. When the values related to sepsis were examined, a strong relationship was determined between sepsis and SOFA score, PRC values, and Lac values in the preseptic period and a weak relationship with NLR. In the model formed using multiple regression analysis with defined cutoff values for the preseptic and the septic periods, we found that in the septic period, a diagnosis of sepsis could be made with 83.8% accuracy. The diagnostic value of the same parameters evaluated in the preseptic period was 77.9%. CONCLUSIONS The diagnostic value of the combination of Lac, PRC, SOFA, and NLR were found to be similar in the preseptic period as the sepsis period; thus these combined values could safely be used for the early diagnosis of sepsis.