TABLE 1.

Threshold values for optimal sensitivity and specificity of EUROimmun and pseudo‐type neutralisation assays by ROC analysis

Cut‐off value	Sensitivity (95% CI)	Specificity (95% CI)
EUROimmun S/CO
6.37	0.95 (0.76, 1.00)	0.89 (0.98, 0.77)
6.64	0.76 (0.53, 0.92)	0.93 (1.00, 0.83)
8.19	0.68 (0.48, 0.83)	0.96 (0.99, 0.85)
9.1 a	0.65 (0.45, 0.81)	1.00 (1.00, 0.92)
10	0.52 (0.30, 0.74)	1.00 (1.00, 1.00)
Pseudo‐type neut. titre
573	0.86 (0.64, 0.97)	0.90 (0.98, 0.73)
770	0.48 (0.26, 0.70)	0.93 (0.99, 0.78)

Note: These calculations are based on 48 samples, from which 22 had neutralising antibody levels of or over 1:100, and the remaining 26 were below 1:100.

^a Optimal value selected for donation selection shown in bold.