Table 1.

Categorization of ultrasound findings

Category	Appendix identified	Diameter	Secondary sign	Binary classification
Positive for appendicitis	Y	>6 mm	Y	Positive
Equivocal (probably positive)	N	N/A	Y	Excluded or considered positive
Equivocal	Y	6-8 mm	N	Equivocal
	N	N/A	Not adequately assessed	(excluded or considered negative)
Equivocal (probably negative)	N	N/A	N	Excluded or considered negative
Negative for appendicitis	Y	<6 mm	N	Negative

Y, yes; N, no; N/A, not available.