For instance, the IL-6 was the most specific predictor (specificity 95.3%) with a high sensitivity (97.0 %) for COVID-19 severity, based on a cut-off of 84.1 pg/mL and an area under the curve (AUC) of 0.675 (95% CI: 0.588-0.761). Here, IL6 is linked to COVID-19.