TABLE 5.

Sensitivity, specificity, and positive and negative predictive values for the detection of C. trachomatis by COBAS AMPLICOR calculated on a sample basis

Sex and symptom category	Specimen	n	% Prevalence	% Sensitivity	% Specificity	% PPVa	% NPVb
Female
Asymptomatic	Endocervical	1,098	7.7	97.6	99.5	94.3	99.8
	Urine		8.1	93.3	99.6	95.4	99.4
Symptomatic	Endocervical	1,138	9.1	96.1	99.2	92.5	99.6
	Urine		9.2	93.3	98.5	86.0	99.3
Male
Asymptomatic	Urethral	710	11.7	98.8	98.7	91.1	99.8
	Urine		12.5	92.1	98.4	89.1	98.9
Symptomatic	Urethral	1,230	19.0	97.4	98.7	94.6	99.4
	Urine		20.6	92.5	98.5	94.0	98.1

^aPPV, positive predictive value. 

^bNPV, negative predictive value.