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Evaluation of PlateliaTM Dengue NS1 Antigen assay for early diagnosis of acute dengue infection

Abstract number: 1733_535

Tabouret M., Salanon C., Sarfati P.

Objectives: In tropical and subtropical region, endemic dengue disease is the most important arbovirosis in terms of morbidity and mortality. To implement appropriate treatment, there is a need for a direct, rapid and specific detection test during the acute phase of the infection. For that purpose, viral culture or nucleic acid detection (performed mainly in reference laboratories) require specialised environment but sometimes with delays to report results. Dengue specific antibodies detection is commonly used even if these antibodies appear several days after onset of symptoms. The objective of the study is to evaluate the performances of PlateliaTM Dengue NS1 Ag (Bio-Rad Laboratories) for early diagnosis of acute dengue infection.

Methods: PlateliaTM Dengue NS1 Ag is a one step sandwich ELISA assay for qualitative detection of Dengue virus NS1 antigen in human serum or plasma. Specificity and sensitivity were determined on 554 healthy blood donors and 297 dengue virus infected patients with accessible clinical information. 157 infected patients (52.9%) were selected based on positive PCR results and because the delay after onset fever was available. Serological status was determined using Dengue IgG indirect and Dengue IgM Capture Panbio assays.

Results: All 554 sera from blood donors were found negative for NS1 giving a specificity of 100%. Sensitivity of NS1 was 91.0% on the 157 PCR positive samples with no significant difference observed between the 4 dengue virus serotypes. NS1 sensitivity was significantly higher (98.5%) in patients with primary dengue infection (PCR+/IgG-) compared to 85.6% in patients with secondary (PCR+/IgG+) dengue infection (Chi2, p < 0.05). During the first 5 days after clinical onset, detection rates ranged from 100.0 to 87.0% for NS1 Ag and from 0.0 to 30.8% for IgM serology. When considering all dengue infected patients, NS1 sensitivity was significantly higher for IgM negative (88.7%) than for IgM positive (66.2%) samples (Chi2, p < 0.0001).

Conclusion: PlateliaTM Dengue NS1 Ag assay is an easy-to-use ELISA for dengue antigen detection. The assay allows early and specific diagnosis of both primary and secondary dengue acute infections. This new test should be considered in diagnostic algorithms to improve patient care monitoring.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Subject:
Location: ICC, Munich, Germany
Presentation type:
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