Table 2.

 Effects of different ways of handling non-evaluable results on pooled diagnostic accuracy values

Basis for calculation	Mean sensitivity (95% CI)	Mean specificity (95% CI)	Area under the curve (95% CI)	Positive likelihood ratio (95% CI)	Negative likelihood ratio (95% CI)
2×2 table (non-evaluable results excluded)	98.2 (96.7 to 99.1)*	89.2 (84.2 to 92.8)	0.99 (0.98 to 1.00)*	9.1 (6.2 to 13.3)*	0.02 (0.01 to 0.04)*
Non-evaluable patients considered as positive	98.3 (96.9 to 99.0)*	78.4 (71.6 to 84.0)	0.98 (0.97 to 0.99)*	4.5 (3.5 to 6.0)	0.02 (0.01 to 0.04)*
Non-evaluable patients considered as negative	92.9 (88.8 to 95.5)	90.5 (86.8 to 93.2)*	0.96 (0.94 to 0.98)	9.8 (7.0 to 13.7)*	0.08 (0.05 to 0.13)
3×2 table (intention to diagnose approach)	92.7 (88.5 to 95.3)	79.0 (72.3 to 84.4)	0.93 (0.91 to 0.95)	4.4 (3.3 to 6.0)	0.09 (0.06 to 0.15)

*Significantly different (P<0.05) from data obtained by use of 3×2 table.