Çiyiltepe et al. highlighted the blood serum effects of Interleukin-6 (IL-6) receptor antagonist tocilizumab (TCZ), an immunosuppressive drug that has improved COVID-19 outcomes in some patients. In this study, TCZ was administered at 8mg/kg by two consecutive intravenous infusions 12 hours apart. 23 patients admitted to ICU for COVID-19 underwent this treatment and were monitored for 28 days. TCZ's effects on blood serum levels of IL-6, lactate dehydrogenase (LDH), D-dimer, and ferritin, were then measured on the first and fifth day of treatment. Overall, decreased levels of CRP and ferritin and increased levels of D-dimer and IL-6 were observed. The increase in IL-6, despite the association with increased COVID-19 severity, can be explained by an inhibition of IL-6R mediated clearance due to TCZ binding to IL-6. Because levels of acute-phase reactants such as CRP, PCT, and ferritin decreased, this data could support the effectiveness of TCZ treatment due to a previously determined association between elevated ferritin levels and poor prognosis. Limitations of this study include retrospective design and a small sample size.