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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%)