TABLE 3.

Comparison of CA and in-house PCR to the adapted gold standard

Specimens	Amplification system	No. of adapted gold standard-positive specimensa that were PCR:		No. of adapted gold standard-negative specimensb that were PCR:		Sensitivity (%)	Specificity (%)	NPV (%)	PPV (%)
		Positive	Negative	Positive	Negative
All (n = 1,527)	CA	67	34	4	1,422	66.33	99.71	97.66	94.36
	In house	92	9	2	1,424	91.08	99.85	99.37	97.87
Smear positive	CA	28	4	0	0	87.50		99.37
(n = 32)c	In house	31	1	0	0	96.87		99.37
Smear negative	CA	39	30	4	1,422	56.52	99.71	97.93	90.69
(n = 1,495)d	In house	61	8	2	1,424	88.40	99.85	99.44	96.82

^aSpecimens from patients with TB (for a definition, see Materials and Methods). 

^bSpecimens from patients without any evidence of TB. 

^cIncludes only specimens from TB patients. 

^dIncludes six unspecific positive smears and 10 smear-positive specimens from patients infected with MOTT.