Fig 1.
Natural progression of disease.
Table 1.
2x2 Table.
Fig 2.
The first graph represents scenarios where ε > 1.
We denote the line tangent to the point of maximum curvature κ from which we derive the radius of curvature R, perpendicular to it. The second graph represents the more rare scenarios where ε < 1. The sensitivity and specificity are constant and were randomly chosen to satisfy the ε condition.
Fig 3.
Sample screening curves as a function of ε.
Fig 4.
The screening curve for the SARS-CoV-2 nasal PCR test (blue) and the prevalence threshold level (red) below which the positive predictive value drops.