Table 2.

Ectopic pregnancy ascertainment performance of the Scholes et al and enhanced ectopic pregnancy algorithms.

Characteristic			Scholes et al algorithm					Enhanced algorithm
			Yes		No		Total		Yes		No	Total
Classification by chart review, n
	Yes	315		19		334		326		8		334
	No	26		140		166		25		141		166
	Total	341		159		500		351		149		500
Test characteristics
	Sensitivity, % (n/N)	N/Aa		N/A		94.3 (315/334)		N/A		N/A		97.6 (326/334)
	Specificity, % (n/N)	N/A		N/A		84.3 (140/166)		N/A		N/A		84.9 (141/166)
	Negative predictive value, % (n/N)	N/A		N/A		88.1 (140/159)		N/A		N/A		94.6 (141/149)
	Positive predictive value, % (n/N)	N/A		N/A		92.4 (315/341)		N/A		N/A		92.9 (326/351)
	Youden index	N/A		N/A		78.6		N/A		N/A		82.5
	F-score	N/A		N/A		93.3		N/A		N/A		95.2

^aN/A: not applicable.