Understanding the factors impacting dengue rapid diagnosis in Bangladesh

Dengue affects over 70 % of the populations in tropical and subtropical regions, including Bangladesh, posing a significant health burden. The sensitivity of widely used rapid diagnostic tests (RDTs) varies due to factors like viral load, serotypes, secondary infections, and disease severity.

This study evaluated the diagnostic performance of RDTs compared to RT-PCR, identifying key factors affecting sensitivity.

The study at Dhaka Medical College (DMC) involved 683 suspected dengue cases. Blood samples and metadata were collected, and RDTs (NS1, IgG, IgM) were performed on-site. Samples were analyzed at icddr,b using RT-PCR for viral RNA detection and serotyping. Diagnostic performance was assessed using MedCalc, while metadata and sensitivity differences were analyzed with SPSS.

We found that vomiting was the most common symptom, followed by, diarrhea, restlessness, and abdominal tenderness. RDT sensitivity was highest in cases with high viral loads, reaching 94 % within 1-3 days of symptom onset and 82 % beyond three days. Moderate viral loads showed sensitivities of 70 % for NS1+IgM and 84 % for NS1+IgM+IgG within three days, decreasing thereafter. Sensitivity was low in low viral load cases but improved after three days with IgG incorporation. DENV-3 and secondary infections showed higher false-negative rates.

The study emphasizes the importance of early testing in suspected dengue cases with symptoms like fever, vomiting, diarrhea, or abdominal tenderness, offering critical insights to enhance diagnostics, patient care, and disease control.