OBJECTIVES: The objective in this study was to examine the prognostic potential of IL-6 in assessing the risk of disease progression in patients with COVID-19. STUDY DESIGN: The study was conducted as a cross-sectional study including historical data. PARTICIPANTS AND METHODS: The patients’ data was collected from the Laboratory Information System database and patients’ medical records. Inclusion criteria were: positive persons over 18 years of age with a positive RT-PCR test for SARS-CoV-2 and complete laboratory processing at admission. The participants were divided into two groups: A) patients in whom disease progression occurred and B) patients with a more mild clinical presentation. The differences between the groups for the examined parameters (IL-6, ferritin, LDH and D-dimers) were tested using the non-parametric Mann-Whitney-U test. The ROC analysis determined the specificity and sensitivity of IL-6 in distinguishing the patients with COVID-19 disease in whom the disease would progress from COVID-19 patients who did not develop severe symptoms. Logistic regression analysis was used to examine potential prediction variables (IL-6, ferritin, LDH, D-dimers, sex, and age) in assessing the disease severity. P < 0,05 represented the significance level used to assess the significance of the results obtained in our study. Diagnostic methods used in this study are RT-PCR (SARS-CoV-2), ECLIA (IL-6), Immunoturbidimetry (D-dimers and ferritin) and UV photometry (LDH). RESULTS: The analysis of the collected data showed that all laboratory parameters used in the study (IL-6, ferrite, LDH and D-dimers) are significantly higher in patients with COVD-19 disease who have developed more severe symptoms. Il-6 and ferritin have proven to be significant predictive markers in the assessment of the outcome of COVD-19 disease. CONCLUSION: IL-6 has a significant prognostic potential and can be used as a biomarker with high specificity (83 %) and sensitivity (81 %) in the risk assessment of the progression of COVD-19 disease.