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Table 5 Prevalence of disease on microscopy (upper part of the table) and qPCR (lower part of the table), N (%, 95% CI) *McNemar to compare sensitivity and specificity present ratio of proportions. All ratios presented as XN-30 relative to HRP-2 and pLDH respectively

From: The XN-30 hematology analyzer for rapid sensitive detection of malaria: a diagnostic accuracy study

XN-30 and RDT (HRP-2 and pLDH) versus corrected microscopy results (n = 837)

 

XN-30

HRP-2

Test ratio

p value

pLDH

Test ratio

p value

Pos

Neg

Pos

Neg

95% CI

 

Pos

Neg

95% CI

 

Microscopy positive

234

3

231

6

  

208

29

  

Microscopy negative

21

579

136

464

  

9

591

  

Sensitivity

98.7%

 

97.5%

 

0.99 (0.97–1.01)

p = .45

87.8%

 

0.89 (0.85–0.93)

p < .0001

Specificity

96.5%

 

77.3%

 

6.47 (4.31–9.73)

p < .0001

98.5%

 

0.43 (0.23–0.81)

p = .012

PPV

91.8%

 

62.9%

   

95.9%

   

NPV

99.5%

 

98.7%

   

95.3%

   

XN-30 and RDT (HRP-2 and pLDH) versus qPCR results (n = 837)

 

XN-30

HRP-2

Test ratio

p value

pLDH

Test ratio

p value

Pos

Neg

Pos

Neg

95% CI

 

Pos

Neg

95% CI

 

qPCR > 0.05 p/μL

253

104

308

49

  

215

142

  

qPCR < 0.05 p/μL

2

478

59

421

  

2

478

  

Sensitivity

70.9%

 

86.3%

 

1.22 (1.15–1.29)

< 0.0001

60.2%

 

0.85 (0.80–0.89)

< .0001

Specificity

99.6%

 

87.7%

 

0.04 (0.01–0.14)

< 0.0001

99.6%

 

1.0 (0.07–13.8)

1.0

PPV

99.2%

 

83.9%

   

99.1%

   

NPV

82.1%

 

89.6%

   

77.1%

   
  1. Pos positive, neg negative, HRP2 histidine-rich protein 2, pLDH pan-Plasmodium lactate dehydrogenase, qPCR qualitative polymerase chain reaction, PPV positive predictive value, NPV negative predictive value