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Table 4 Comparison of sensitivity and specificity of three LAMP tests based on calcein visualization with different DNA extracts. Values in brackets represent the 95% CI

From: Evaluation of different DNA extraction methods and loop-mediated isothermal amplification primers for the detection of Mycobacterium ulcerans in clinical specimens

  LAMP WITH MODIFIED BOOM DNA EXTRACTS  
BURULI Primers MU 2404 Primers BU-LAMP Primers
(+) (−) Total (+) (−) Total (+) (−) Total
IS2404 PCR (+) 86 8 94 81 13 94 54 40 94
IS2404 PCR (−) 1 41 42 5 37 42 0 42 42
Total 87 49 136 86 50 136 54 82 136
Disease prevalence 69.12% (60.63 to 76.75%) 69.12% (60.63 to 76.75%) 69.12% (60.63 to 76.75%)
Sensitivity 91.49% (83.92 to 96.25%) 86.17% (77.51 to 92.43%) 57.45% (46.82 to 67.59%)
Specificity 97.62% (87.43 to 99.94%) 88.10% (74.37 to 96.02%) 100.00% (91.59 to 100.00%)
Positive Predictive Value 98.85% (92.53 to 99.83%) 94.19% (87.64 to 97.37%) 100%
Negative Predictive Value 83.67% (72.50 to 90.88%) 74.00% (62.93 to 82.67%) 51.22% (45.36 to 57.04%)
Accuracy 93.38% (87.81 to 96.93%) 86.76% (79.89 to 91.96%) 70.59% (62.17 to 78.09%)
LAMP WITH EasyNAT DNA EXTRACTS  
BURULI Primers MU 2404 Primers BU-LAMP Primers
(+) (−) Total (+) (−) Total (+) (−) Total
IS2404 PCR (+) 70 10 80 59 21 80 38 42 80
IS2404 PCR (−) 0 56 56 1 55 56 1 55 56
Total 70 66 136 60 76 136 39 97 136
Disease prevalence 58.82% (50.07 to 67.19%) 58.82% (50.07 to 67.19%) 58.82% (50.07 to 67.19%)
Sensitivity 87.50% (78.21 to 93.84%) 73.75% (62.71 to 82.96%) 47.50% (36.21 to 58.98%)
Specificity 100.00% (93.62 to 100.00%) 98.21% (90.45 to 99.95%) 98.21% (90.45 to 99.95%)
Positive Predictive Value 100% 98.33% (89.39 to 99.76%) 97.44% (84.31 to 99.63%)
Negative Predictive Value 84.85% (75.82 to 90.91%) 72.37% (64.42 to 79.11%) 56.70% (51.46 to 61.80%)
Accuracy 92.65% (86.89 to 96.42%) 83.82% (76.54 to 89.58%) 68.38% (59.86 to 76.08%)
LAMP WITH MODIFIED EasyNAT DNA EXTRACTS  
BURULI Primers MU 2404 Primers BU-LAMP Primers
(+) (−) Total (+) (−) Total (+) (−) Total
IS2404 PCR (+) 64 7 71 59 12 71 25 46 71
IS2404 PCR (−) 7 58 65 4 61 65 3 62 65
Total 71 65 136 63 73 136 28 108 136
Disease prevalence 52.21% (43.48 to 60.84%) 52.21% (43.48 to 60.84%) 52.21% (43.48 to 60.84%)
Sensitivity 90.14% (80.74 to 95.94%) 83.10% (72.34 to 90.95%) 35.21% (24.24 to 47.46%)
Specificity 89.23% (79.06 to 95.56%) 93.85% (84.99 to 98.30%) 95.38% (87.10 to 99.04%)
Positive Predictive Value 90.14% (81.89 to 94.87%) 93.65% (85.02 to 97.46%) 89.29% (72.53 to 96.34%)
Negative Predictive Value 89.23% (80.32 to 94.39%) 83.56% (75.15 to 89.52%) 57.41% (52.97 to 61.73%)
Accuracy 89.71% (83.33 to 94.26%) 88.24% (81.60 to 93.12%) 63.97% (55.30 to 72.02%)