The aim of the studyis to substantiate the efficacy of new prognostic criteria in diagnosing non-alcoholic hepatic steatosis at early stages of its development.Materials and MethodsPatients with excessive body mass (n=26) and obesity (n=28) having different concomitant pathologies of the digestive organs have undergone a comprehensive examination including assessment of biochemical blood indices, ultrasound examination of the abdominal organs, dynamic hepatobiliscintigraphy, assessment of the comorbidity level as a whole (calculation of CIRS) and by the available pathology of the digestive organs.ResultsThe ultrasound signs of hepatic steatosis have been found in all patients with obesity stage II and III, in 69.2% of the examined patients (95% CI: 42.37–87.32) with obesity stage I, in 30.8% (95% CI: 16.50–49.99) with excessive body mass, and in 13.9% of patients (95% CI: 6.08–28.66) with normal body mass. According to the ROC analysis, the predictors of hepatic steatosis development in patients with excessive body mass and obesity are BMI (>31, р<0.0001) and the number of digestive organ illnesses (more than 4 diseases, p<0.0001). On the basis of the data obtained, a logistic model has been developed in the form of the regression equation permitting us to predict the groups of patients with a low or high degree of risk of hepatic steatosis. The analysis of dynamic hepatobiliscintigraphy has revealed deceleration of the absorbing function of hepatocytes in patients with normal ultrasound images of the liver even in case of excessive body mass. The obtained results made it possible to develop a method of diagnosing fatty hepatosis with subsequent calculation of the functional hepatocyte activity index (FHAI) which helps not only establish functional disorders but identify the group of patients having the risk of developing these disorders. Normal ultrasound imaging of the liver and absence of the biochemical changes in the blood are not indicators of preservation of its functional activity, since the risk of functional disorders was found in 32.3% of cases (95% CI: 18.57–49.86) and reversible disorders in 19.3% (95% CI: 9.19–36.28) when FHAI was calculated for patients with normal body mass. With the increase of body mass, irreversible functional disorders of hepatocytes are observed in 80–100% of patients.Thus, the results obtained in the course of the investigation have confirmed the possibility of using new prognostic markers of hepatic steatosis for early diagnosis of non-alcoholic fatty liver disease.