FIG. 1.

Evaluation of sensitivity and specificity of recombinant nucleocapsid protein-based IgM (A) and IgA (B) antibody ELISA for SARS-CoV pneumonia. Serum specimens were obtained from 106 patients with SARS-CoV pneumonia, and control serum specimens were obtained from 149 healthy blood donors. The test results were plotted as OD₄₅₀. The cutoff line for positive diagnosis is drawn at a value that equals the sum of the mean value and two times the standard deviation for the healthy blood donors.