Table 2.

Assay performance simulating high-volume CT/NG testing (n = 555^*), results for Chlamydia trachomatis^†

		Aptima Combo 2
		CT positive	CT negative	Total
cobas CT/NG	CT positive	31	1	32
	CT negative	0	523	523
	Total	31	524	555
PPA (95% CI), NPA (95% CI)		100 (88.8, 100)	99.8 (98.9, 100)
OPA (95% CI)		99.8 (99, 100)
p-value‡		1

^*One CT specimen was not included in the CT method correlation because of an equivocal result generated by the Aptima Combo 2 assay (cobas CT/NG: “CT Positive” and Aptima Combo 2: “CT UNBEST”)

^†Comparison of cobas CT/NG for use on the cobas 6800 system and Aptima Combo 2 on the Panther system

^‡Calculated using McNemar’s test

Abbreviations: CI confidence interval, CT Chlamydia trachomatis, NPA negative percent agreement, OPA overall percent agreement, PPA positive percent agreement