Skip to main content

Table 3 RDT performances compared to various parameters on 196 and 133 undiluted and 1:100-diluted specimens, respectively

From: Strategy using a new antigenic test for rapid diagnosis of Streptococcus pneumoniae infection in respiratory samples from children consulting at hospital

RDT results

S. pneumoniae positive culture

Positive

Negative

Sensitivity

% (IC 95%)

Specificity

% (IC 95%)

PPV

% (IC 95%)

NPV

% (IC 95%)

RDT undiluted

  

100 (94.8–100)

50.4 (41.4–58.6)

52.6 (48.3–56.9)

100 (94.3–100)

 Positive

70

63

    

 Negative

0

63

    

RDT diluted

  

91.4 (82.5–96)

80.9 (69.6–88.7)

84.2 (76.1–89.9)

89.5 (79.8–94.9)

 Positive

64

12

    

 Negative

6

51

    
 

S. pneumoniae culture ≥107 CFU/ml

Positive

Negative

Sensitivity

% (IC 95%)

Specificity

% (IC 95%)

PPV

% (IC 95%)

NPV

% (IC 95%)

RDT undiluted

  

100 (92.9–100)

43.1 (35.4–51.2)

37.6 (34.3–41)

100 (94.3–100)

 Positive

50

83

    

 Negative

0

63

    

RDT diluted

  

94.6 (92.9–100)

68.7 (58.1–77.4)

65.8 (58.3–72.6)

100 (93.7–100)

 Positive

50

26

    

 Negative

0

57

    
 

Quantitative PCR for ply gene Ct < 22

Positive

Negative

Sensitivity

% (IC 95%)

Specificity

% (IC 95%)

PPV

% (IC 95%)

NPV

% (IC 95%)

RDT undiluted

  

98.4 (91.5–99.7)

46.6 (38.3–55.1)

46.6 (42.7–50.7)

98.4 (89.8–99.8)

 Positive

62

71

    

 Negative

1

62

    

RDT diluted

  

91.9 (82.5–96.5)

73.2 (61.9–82.1)

75 (67–81.6)

91.2 (82–96)

 Positive

57

19

    

 Negative

5

52

    
 

Quantitative PCR for lytA gene Ct < 23

Positive

Negative

Sensitivity

% (IC 95%)

Specificity

% (IC 95%)

PPV

% (IC 95%)

NPV

% (IC 95%)

RDT undiluted

  

100 (87.5–100)

37.3 (30.3–44.8)

20.3 (18.5–22.3)

100 (94.3–100)

 Positive

27

106

    

 Negative

0

63

    

RDT diluted

  

96.3 (81.7–99.3)

52.8 (43.4–62.1)

34.2 (29.6–39.2)

98.3 (89–99.7)

 Positive

26

50

    

 Negative

1

56

    
 

S. pneumoniae pneumonia

Positive

Negative

Sensitivity

% (IC 95%)

Specificity

% (IC 95%)

PPV

% (IC 95%)

NPV

% (IC 95%)

RDT undiluted

  

100 (85.7–100)

36.4 (29.6–43.8)

17.3 (15.7–19)

100 (94.3–100)

 Positive

23

110

    

 Negative

0

63

    

RDT diluted

  

100 (85.7–100)

51.8 (42.6–60.9)

30.3 (26.3–34.5)

100 (93.7–100)

 Positive

23

53

    

 Negative

0

57

    
  1. PPV positive predictive value, NPV negative predictive value
Back to article page

BMC Microbiology

ISSN: 1471-2180

Contact us