Clinical applicability of various dengue diagnostic tests in resource-limited endemic settings

Abstract

Introduction: Dengue is one of the most important arboviral infections caused by one of the four dengue serotypes, 1-4. Objective: To study the applicability of different diagnostic methods in diagnosis of dengue viral infection. Materials and Methods: A total of 2101 blood samples were collected for confirmation of dengue viral infection. All the samples were tested by dengue-specific IgM ELISA, of which 111 were also tested for NS1 antigen detection and 27 acute samples (≤5 days) were further subjected for viral RNA detection by RT-PCR and isolation in C6/36 cell line. To detect the sensitivity of NS1 antigen for different dengue virus serotypes, four dengue serotype 1 and 12 dengue 3 were subjected for the NS1 antigen assay. Results: Most common age group affected was 16-45 years, with male to female ratio of 2.8:1. During first 3 days of illness virus isolation and RT-PCR were the most sensitive (83%) followed by NS1 antigen detection (75%) and IgM detection (37.5%). The positivity of IgM detection was found to be significantly higher as compared to NS1 detection during 4 to 5 days and also after 5 days of illness (P < 0.05). Dengue serotypes 1 and 3 were found to be co-circulated, dengue 1 being the predominant serotype. Conclusion: Virus isolation and RT-PCR were the most sensitive tests during the early period of illness whereas beyond third day, IgM antibody detection was found to be the most sensitive method of dengue diagnosis.

Keywords

• Dengue
• Diagnosis
• IgM antibody
• NS1 Ag
• RT-PCR