Early diagnosis of dengue in travelers: Comparison of a novel real-time RT-PCR, NS1 antigen detection and serology
Received 18 August 2009; accepted 4 November 2009. published online 07 December 2009.
Abstract
Background
The increased traveling to dengue endemic regions and the numerous epidemics have led to a rise in imported dengue. The laboratory diagnosis of acute dengue requires several types of tests and often paired samples are needed for obtaining reliable results. Although several diagnostic methods are available, proper comparative data on their performance are lacking.
Objectives
To compare the performance of novel methods including a novel pan-DENV real-time RT-PCR and a commercially available NS1 capture-EIA in regard to IgM detection for optimizing the early diagnosis of DENV in travelers.
Study design
A panel of 99 selected early phase serum samples of dengue patients was studied by real-time RT-PCR, NS1 antigen ELISA, IgM-EIA, IgG-IFA and cell culture virus isolation.
Results
The novel real-time RT-PCR was shown specific and sensitive for detection of DENV-1-4 RNA and suitable for diagnostic use. The diagnostic rate using combination of RNA and IgM detection was 99% and using NS1 and IgM detection 95.9%. The results of RNA and NS1 antigen detection disagreed in 15.5% of samples that had only RNA or NS1 antigen detected.
Conclusions
The diagnostic rates of early samples are higher when either RNA or NS1 antigen detection is combined with IgM detection. Besides the differences in the RNA and NS1 detection assays, the observed discrepancy of results could suggest individual variation or differences in timing of these markers in patient serum.
aDepartment of Virology, Haartman Institute, Faculty of Medicine, University of Helsinki, P.O. Box 21 (Haartmaninkatu 3), FI-00014 University of Helsinki, Finland
bHelsinki University Central Hospital, Department of Medicine, Division of Infectious Diseases, Helsinki, Finland
cCentres for Military Medicine and for Biological Threat Preparedness, Tukholmankatu 8A, 00290 Helsinki, Finland
dDepartment of Virology, HUSLAB, Helsinki University Central Hospital Laboratory, P.O. Box 400 (Haartmaninkatu 3), FI-00029 HUS, Finland
eDivision of Microbiology and Epidemiology, Department of Basic Veterinary Sciences, P.O. Box 66 (Agnes Sjöbergin katu 2), FI-00014 University of Helsinki, Finland
ABSTRACT