IL6 and COVID-19: At a cut-off of 35 pg/ml, IL-6 effectively differentiated COVID-19 patients who received mechanical ventilation, with a sensitivity of 95.2% (95% CI 77.3 – 99.2), specificity of 56.8% (95% CI 42.2 – 70.3), PPV of 51.3% (95% CI 36.2 – 66.1) and NPV of 96.2% (95% CI 81.1 – 99.3).