Table 2 Diagnostic accuracy of rt-LAMP for pulmonary TB in adults, compared with MRS (culture MGIT), Xpert MTB/RIF and sputum smear tests.

From: Validation study of a novel, rapid, open platform real-time LAMP assay for early diagnosis of pulmonary tuberculosis

Patient population

Test accurarcy*

Likelihood ratio*

Predictive value*

Kappa value (95% CI)

Youden index

rt-LAMP for PTB, In MRS

Se: 89.36 (76.9 to 96.45)

LR + : 15.04 (9.51 to 23.80)

PPV: 70 (59.59 to 78.69)

0.75 (0.64 to 0.84)

0.83

Sp: 94.06 (90.77 to 96.44)

LR-: 0.11 (0.05 to 0.26)

NPV: 98.28 (96.14 to 99.24)

rt-LAMP PTB, in Xpert MTB/RIF

Se: 93.33 (83.80 to 98.15)

LR + : 67.67 (25.51 to 79.50)

PPV: 93.33 (84.07 to 97.38)

0.92 (0.86 to 0.97)

0.91

Sp: 98.62 (96.51 to 99.62)

LR-: 0.07 (0.03 to 0.17)

NPV: 98.62 (96.52 to 99.46)

rt-LAMP PTB in SS, MRS

Se: 100 (87.66 to 100%)

LR + : 138 (34.69 to 549.01)

PPV: 93.33 (77.87 to 98.24)

0.96 (0.91 to 1.00)

0.99

Sp: 99.28 (97.41 to 99.91)

LR-: 0

NPV: 100 (98.66 to 100)

rt-LAMP PTB in SS-, MRS

Se: 73.68 (48.80 to 90.85)

LR + : 17.56 (9.49 to 32.50)

PPV: 53.85 (38.67 to 68.35)

0.59 (0.42 to 0.77)

0.69

Sp: 95.8 (92.79 to 97.81)

LR-: 0.27 (0.13 to 0.58)

NPV: 98.21 (96.27 to 99.15)

rt-LAMP in SS, Xpert MTB/RIF, MRS

Se: 100 (87.66 to 100%)

LR + : 138 (34.69 to 549.01)

PPV: 93.33 (77.87 to 98.24)

0.96 (0.91 to 1.00)

0.99

Sp: 99.28 (97.41 to 99.91)

LR-: 0

NPV: 100 (98.66 to 100)

  1. PTB pulmonary tuberculosis, rt-LAMP real-time LAMP, MRS microbiological reference standard (MGIT culture), SS sputum smear, SS− sputum smear negative, Se sensitivity, Sp specificity, TP true positive, TN true negative, LR +  positive likelihood ratio, LR− negative likelihood ratio, PPV positive predictive value, NPV negative predictive value, CI confidence interval.
  2. *Values are percentages (95% confidence interval).
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