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Table 3 Performance of TB-LAMP test in the diagnosis of TB determined using various reference standards

From: Performance of loop-mediated isothermal amplification assay in the diagnosis of pulmonary tuberculosis in a high prevalence TB/HIV rural setting in Uganda

Population Diagnostic performance measure TB-LAMP performance % (95% CI)
LJ and /or MGIT MTB as reference standard MTB culture and/or Xpert MTB/Rif test as reference
Overall performance, N = 233 Sensitivity 46/83, 55.4 (44.1-66.3) 47/95, 49.5 (39.1-59.9)
Specificity 147/150, 98.0 (94.3-99.6) 136/138, 98.6 (94.9-99.8)
PPV 46/49, 93.9 (83.1-98.7) 47/49, 95.9 (86.0-99.5)
NPV 147/184, 79.9 (73.4-85.4) 136/184, 73.9 (66.9-80.1)
LR (positive) 27.7 (8.9-86.4) 34.1 (8.5-137.2)
LR (negative) 0.45 (0.36-0.58) 0.51 (0.42-0.63)
Smear-negatives, N = 190 Sensitivity 11/45, 24.4 (12.9-39.5) 11/56, 19.6 (10.2- 32.4)
Specificity 143/145, 98.6 (95.1-99.8) 132/134, 98.5 (94.7-99.8)
PPV 11/13, 84.6 (54.6-98.1) 11/13, 84.6 (54.6-98.1)
NPV 143/177, 80.8 (74.2-86.3) 132/177, 74.6 (67.5-80.8)
LR (positive) 17.72 (4.08 -77.0) 13.16 (3.01-57.47)
LR (negative) 0.77 (0.65-0.91) 0.82 (0.72-0.93)
HIV-infected, N = 113 Sensitivity 23/44, 52.3 (36.7-67.5) 24/50, 48.0 (33.7-62.6)
Specificity 67/69, 97.1 (89.9-99.6) 62/63, 98.4 (91.5-100)
PPV 23/25, 92.0 (74.0-99.0) 24/25, 96.0 (79.6-99.9)
NPV 67/88, 76.1 (65.9-84.6) 62/88, 70.5 (59.8-79.7)
LR (positive) 18.0 (4.47-72.7) 30.24 (4.24-215.9)
LR (negative) 0.49 (0.36-0.67) 0.53 (0.40-0.69)
Smear-negative HIV-infected, N = 96 Sensitivity 08/28, 28.6 (13.2-48.7) 08/33, 24.2 (11.1- 42.3)
Specificity 67/68, 98.5 (92.1-100) 62/63, 98.4 (91.5-100)
PPV 08/09, 88.9 (51.8- 99.7) 08/09, 88.9 (51.8- 99.7)
NPV 67/87, 77.0 (66.8-85.4) 62/87, 71.3 (60.6-80.5)
LR (positive) 19.43 (2.55-148.19) 15.27 (1.99-116.96)
LR (negative) 0.72 (0.57- 0.92) 0.77 (0.63- 0.94)
Hospital, N = 126 Sensitivity 23/37, 62.2% (44.8-77.5) 23/42, 54.8 (38.7-70.2)
Specificity 87/89, 97.8% (92.1-99.7) 82/84, 97.6 (91.7-99.7)
PPV 23/25, 92.0 (74.0 -99.0) 23/25, 92.0 (74.0-99.0)
NPV 87/101, 86.1 (77.8-92.2) 82/101, 81.2 (72.2-88.3)
Health centre III, N = 107 Sensitivity 23/46, 50.0% (34.9-65.1) 24/53, 45.3 (31.6-59.6)
Specificity 60/61, 98.4% (91.2-100) 54/54, 100 (93.4-100.0)
PPV 23/24, 95.8 (78.9-99.9) 24/24, 100.0 (85.8 -100.0)
NPV 60/83, 72.3 (61.4-81.6) 54/83, 65.1 (53.8-75.2)
  1. PPV Positive predictive value, NPV Negative predictive value, LR Likelihood ratio, CI Confidence intervals, FM fluorescence microscopy, ZN Ziehl-Neelson, MGIT mycobacterial growth indicator tube, LJ Lowenstein-Jensen