Evaluation Report 

Diagnosing Dengue at the Point-of-Care: Utility of a Rapid Combined Diagnostic Kit in Singapore

PLoS ONE 9(3): e90037. doi:10.1371/journal.pone.0090037


Introduction

In search of a rapid diagnostic tool to be used at the point-of-care, we performed an evaluation of combination rapid testing combining NS1 antigen and IgM/IgG detection against a WHO-based composite reference standard based on serial blood sampling. SD Dengue Duo was chosen, as it has shown good performance in multiple laboratory-based trials with sensitivities and specificities.


Specimens

  • Total: 224 whole blood samples
  • Confirmed dengue: 147
  • Confirmed not dengue: 50
  • Non-conclusive: 47


Results

1) Performance against laboratory-based tests

Test Sensitivity Specificcity PPV NPV
Dengue Duo (NS1/IgG/IgM) 93.9 92 97.2 83.6
Dengue Duo (NS1/IgM) 91.8 96 98.5 80
Dengue Duo (NS1) 81.6 98 99.2 64.5
WHO 1997 then Dengue Duo 91.2 94 97.8 78.3
WHO 2009 then Dengue Duo
91.21 94 97.8 78.3

2) Sensitivity of SD Dengue Duo in different subpopulations

Subpopulation POCT NS1 or IgM or IgG POCT NS1 or IgM POCT NS1
Fever<=5 days(n=50) 90 88 86
Fever>5 days(n=97)
95.9 93.8 79.4
DENV-1 (n=22) 100 95.5 86.4
DENV-2 (n=89) 94.4 94.4 87.6


Conclusions

The use of a combination RDT fulfills WHO ASSURED criteria for point-of-care testing and can enhance dengue diagnosis in an endemic setting. This has the potential to markedly improve clinical management of dengue in the field.