Diagnostic utility of GeneXpert MTB/RIF assay versus conventional methods for diagnosis of pulmonary and extra-pulmonary tuberculosis

Table 2 Comparison between PTB and EPTB regarding laboratory diagnostic methods (AFB smear, LJ culture and Gene Xpert MTB/RIF assay)

Laboratory methods	PTB(n = 449)	EPTB(n = 133)	X²	Pvalue
AFB smear
Negative	300 (66.8%)	81 (60.9%)	2.22	0.70
+	40 (8.9%)	12 (9.0%)
++	31 (6.9%)	10 (7.5%)
+++	44 (9.8%)	18 (13.5%)
++++	34 (7.6%)	12 (9.0%)
AFB smear
Negative	300 (66.8%)	81 (60.9%)	1.59	0.21
Positive	149 (33.2%)	52 (39.1%)	1.59	0.21
LJ culture
Positive	122 (27.2%)	38 (28.6%)	0.10	0.75
Negative	327 (72.8%)	95 (71.4%)	0.10	0.75
Gene Xpert MTB/RIF assay
Invalid	42 (9.4%)	11 (8.3%)	1.55	0.46
Positive	111 (24.7%)	40 (30.1%)
Negative	296 (65.9%)	82 (61.7%)
Rifampicin resistance	(n = 111)	(n = 40)
Yes	14 (12.6%)	13 (32.5%)	7.92	0.005*
No	97 (87.4%)	27 (67.5%)	7.92	0.005*

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