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Table 3 Sensitivity, specificity, PPV and NPV of PfHRP-2/pLDH RDT for detecting Plasmodium falciparum against nested PCR as a reference method

From: Field evaluation of a PfHRP-2/pLDH rapid diagnostic test and light microscopy for diagnosis and screening of falciparum malaria during the peak seasonal transmission in an endemic area in Yemen

 

PCR + ve

PCR + ve

PCR−ve

PCR−ve

Sensitivity

Specificity

PPV

NPV

% Agreement*

RDT + ve

RDT−ve

RDT−ve

RDT + ve

% (95 % CI)

% (95 % CI)

% (95 % CI)

% (95 % CI)

(Kc)

Overall

119

5

47

37

96.0 (90.9–98.3)

56.0 (44.7–66.8)

76.3 (69.0–82.3)

90.4 (78.8–96.8)

79.8 (0.553)

Age (years) (n = 208)

 ≥10

100

5

41

32

95.2 (89.3–97.9)

56.2 (44.1–67.8)

75.8 (67.8–82.3)

89.1 (76.4–96.4)

79.2 (0.545)

 <10

19

0

6

5

100 (82.4–100)

54.6 (23.4–83.3)

79.2 (57.9–92.9)

100 (54.1–100)

83.3 (0.603)

Fever 48 h prior to survey (n = 208)

 Yes

42

0

2

2a

100 (92.3–100)

50.0 (6.8–93.2)

95.5 (84.9–98.7)

100 (15.8–100)

95.3 (0.646)

 No

77

5

45

35

93.9 (86.3–98.0)

56.3 (44.7–67.3)

68.8 (59.3–77.2)

90.0 (78.2–96.7)

75.3 (0.504)

History of anti-malarial drug intake 1 week prior to the survey (n = 207)

 Yes

52

2

9

21

96.3 (87.5–99.0)

30 (14.7–49.4)

71.2 (60.0–80.3)

81.8 (48.2–97.7)

72.6 (0.306)

 No

66

3

38

16

95.7 (88.0–98.5)

70.4 (57.2–80.9)

80.5 (70.6–87.6)

92.7 (80.6–97.5)

84.6 (0.678)

  1. CI confidence interval, PfHRP-2 P. falciparum histidine-rich protein-2, pLDH Plasmodium lactate dehydrogenase, RDT rapid diagnostic test, PCR polymerase chain reaction, PPV positive predictive value, NPV negative predictive value, Kc Cohen’s kappa coefficient;  % agreement was calculated by summation of the number of positives and negatives by both RDT and PCR divided by the total number of cases
  2. * The agreement between RDT and PCR was significant for all categories with p < 0.001
  3. aParasite densities of these two cases were 80 parasites and 400 parasites/µL