Table 2 Performance of line probe assay (LPA) in detecting rifampicin, isoniazid and multidrug-resistance from smear-positive sputum specimens

No. resistant/No. susceptible strains

15/77

26/66

13/79

13/79

Sensitivity, %

(95% CI)

100.0%

(78.2 - 100.0)*

80.8%

(60.6 - 93.4)

92.3%

(64.0 - 99.8)

100.0%

(75.3-100.0)*

Specificity, %

(95% CI)

96.1%

(89.0 - 99.2)

100.0%

(94.5 - 100.0)*

96.2%

(89.3 - 99.2)

96.2%

(89.3 - 99.2)

Overall accuracy, % (95% CI)

96.7%

(90.8 - 99.3)

94.6

(87.8 - 98.2)

95.7%

(89.2 - 98.8)

96.7%

(90.7 - 99.3)

PPV, %

(95% CI)

83.3%

(58.6 - 96.4)

100.0%

(83.9 - 100.0) *

80.0%

(51.9 - 95.7)

81.3%

(54.3 - 96.0)

NPV, %

(95% CI)

100.0%

(95.1 - 100.0)

93.0%

(84.3 - 97.7)

98.7%

(92.9 - 100.0)

100.0%

(95.3 - 100.0)*