TABLE 3.

Test results for clinical strains of MDR M. tuberculosis (n = 133) for susceptibility to second-line drugs

Antibiotic (concn [μg/ml])	MGIT 960 resulta	RRM/MPAa,b results		Rate of agreement (%)	Sensitivityc (%)	Specificityd (%)	PPVe (%)	NPVf (%)
		S	R
AMI (1.0)	S	108	1	99	96	99	96	99
R	23
CAP (1.25)	S	105	2	97	92	98	92	98
R	2	24
OFL (1.0)b	S	97		100	100	100	100	100
R	34
RIFB (0.5)	S	6	2	99	98	100	100	75
R	125
PRO (2.5)	S	119	3	96	75	98	82	98
R	2	9
PRO (5.0)	S	124	3	97	63	99	83	98
	R		5

^aS, susceptible; R, resistant.

^bValues are numbers of isolates. A total of 132 M. tuberculosis clinical isolates were tested.

^cThe sensitivity, i.e., the ability of MGIT 960 to detect true resistance compared with the RRM results.

^dThe specificity, i.e., the ability of MGIT 960 to detect true susceptibility compared with the RRM results.

^ePPV, positive predictive value.

^fNPV, negative predictive value.