AVP and COVID-19: Abnormalities such as hyponatremia are well-known to be associated with the presence and severity of COVID-19.18–20 Potentially related to the syndrome of inappropriate antidiuretic hormone section, sodium levels may be particularly useful as COVID-19 indicators in patients with atypical, nonrespiratory presentations.21,22 A COVID-19 risk stratification system could benefit from the incorporation of information related to white blood cell (WBC) count.