As such, independent of COVID-19, a pattern of high serum ferritin (iron-storage protein) but low serum iron and low transferrin (iron-carrier protein in circulation) within 3 days of ICU admission has been seen in more than 75% of critically ill patients [4], indicating the significance of iron and related proteins in critical illness, and critical illness is seen in COVID-19 cases. Here, TF is linked to COVID-19.