Inclusion Criteria:  Whole blood specimen collected in EDTA anticoagulant tubes Subject is considered to have severe or critical illness per below:  Severe Illness  SpO2 < 94% on room air at sea level; Ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/FiO2) < 300 mmHg; Respiratory frequency > 30 breaths/min; Or lung infiltrates >50% Critical Illness  a) Respiratory failure; b) Septic shock; c) And/or multiple organ dysfunction d) At least one criteria of severe illness  Subject confirmed to be COVID-19 positive by an EUA RT-PCR test Subject is 18+ years of age Minimum volume of 100µL for Symphony IL-6 testing Specimen is available for testing within 12 hours from collection  Exclusion Criteria:  Subject is receiving an anti-IL-6 treatment Subject is receiving corticosteroids Hemolyzed specimens