Low Sensitivity of NS1 Protein Tests Evidenced during a Dengue Type 2 Virus Outbreak in Santos, Brazil, in 2010
Alvina Clara Félixa, Camila Malta Romanoa, Cristiane de Campos Centronea, Celia L. de Lima Rodriguesa, Lucy Santos Villas-Boasa, Evaldo Stanislau Affonso de Araújoa b, Andréia Manso de Matosc, Karina Inacio Carvalhoc, Celina Maria Turchi Martellid, Esper Georges Kallasc, Claúdio Sérgio Pannutia, José Eduardo Levia
- aInstituto de Medicina Tropical de São Paulo e Departamento de Moléstias Infecciosas e Parasitárias (LIMHC) da Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
- bHospital Ana Costa, Santos, Brazil
- cDisciplina de Imunologia Clínica e Alergia (LIM-60), Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
- dInstituto de Patologia Tropical e Saúde Pública (IPTSP), Universidade Federal de Goiás, Goiânia, Brazil
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Abstract
In 2010, a large outbreak of dengue occurred in Santos, Brazil. The detection of the NS1 antigen was used for diagnosis in addition to the detection of IgG, IgM, and RNA. A large number of NS1 false-negative results were obtained. A total of 379 RNA-positive samples were selected for thorough evaluation. NS1 was reactive in 37.7% of cases. Most of the cases were characterized as a secondary infection by dengue 2 virus. Sequencing of NS1 positive and negative isolates did not reveal any mutation that could justify the diagnostic failure. Use of existing NS1 tests in the Brazilian population may present a low negative predictive value, and they should be used with caution, preferentially after performing a validation with samples freshly obtained during the ongoing epidemic.
TL;DRUse of existing NS1 tests in the Brazilian population may present a low negative predictive value, and they should be used with caution, preferentially after performing a validation with samples freshly obtained during the ongoing epidemic. (Semantic Scholar)