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