The Challenge of Using an Antigen Test as a Screening Tool for SARS-CoV-2 Infection in an Emergency Department: Experience of a Tertiary Care Hospital in Southern Italy

Figure 2

Nomogram of the positive (blue) and negative (red) likelihood ratio, and prior and posterior probabilities. Positive test: positive likelihood ratio: 37; 95% confidence interval: [23–58]; posterior probability (odds): 92% (11.5); 95% confidence interval: [88–95%]; (~1 in 1.1 with a positive test was sick). Negative test: negative likelihood ratio: 0.05; 95% confidence interval: [0.03–0.09]; posterior probability (odds): 2% (0.0); 95% confidence interval: [1–3%]; (~1 in 1.0 with a negative test was well).