In addition to what is already known, our study provided important insights about COVID-19: first, we provided the cut-off values and optimal time point for measurement of D-dimer (> 1 μg/mL), LDH, ALC (<1,100), and albumin (< 40 g/L); second, we reported cytokines that are significantly affected by COVID-19 and their use in predicting disease progression and mortality; third, we provided insights on the dynamics of IL-6 in the course of COVID-19 disease. This evidence concerns the gene IL6 and COVID-19.