Paper-Based Dengue NS1 Rapid Diagnostic Test Validated

About 70% of the 3.9 billion people at risk live in Asian Pacific countries, mainly in Southeast Asia.

The early diagnosis of dengue is essential for clinical assessment, investigations, and disease control. Although, molecular assays were used as the gold standard for diagnosing dengue infection, these methods are expensive, tedious, and need the expertise of technicians, which is unsuitable for point-of-care tests in remote areas.

A multi-disciplinary team of scientists working with those at King Mongkut’s University of Technology Thonburi (Bangkok, Thailand) analyzed 250 dengue-suspected sera samples used in a study were the archived sera of dengue-suspected patients, routinely collected during the peak of the disease epidemic in Thailand, from July to September 2019. Patients’ blood samples were routinely tested by a commercial dengue NS1 test kit (Dengue Duo test, SD BIOLINE, Abbott Park, IL, USA), immediately after collection to diagnose and treat patients.

The team developed a simple diagnostic kit for dengue NS1 testing based on a wax-printed microfluidic paper-based analytical device (μPAD), so-called DEN-NS1-PAD for sensitive and specific detection of dengue NS1. The DEN-NS1-PAD allows specific interaction between reporter antibodies (rAb) labeled with Gold Nanoparticles (AuNPs) and dengue NS1 protein. Viral RNAs in serum samples were extracted by using QIAamp Viral RNA Mini Kit (QIAGEN, Hilden, Germany). They were then subjected to RT-PCR using dengue-specific primers, and the RT-PCR products were used as templates for the nested-PCR reaction.

The team reported that out of the 250 dengue-suspected patients who were admitted to the hospital over the study period, there were two commercialized RDT tested, of which 219 were from SD BIOLINE Dengue Duo test and PCR testing. Prevalence of dengue infection was 45.21% by SD-NS1, 47.49% by DEN-NS1-PAD and 45.21% by nested-PCR. The results from the nested-PCR were 99 of dengue positive and 120 negative. The limit of detection of DEN-NS1-PAD was 0.78 ng/mL. It showed 88.89% sensitivity, 86.67% specificity, and a substantial agreement correlation compared with nested-PCR. In contrast, SD BIOLINE for NS1 (SD-NS1) detection showed 87.88% sensitivity, 90.00% specificity, and also had a substantial agreement correlation with nested-PCR.

The authors concluded that the performance of the DEN-NS1-PAD to be almost on par with SD-NS1 in detecting dengue infection in acute febrile cases. The device possesses better sensitivity than SD-NS1, especially for the diagnosed patient after day five of illness. The DEN-NS1-PAD can be a potential alternative to existing commercial RDTs in the detection of acute dengue infection in the future. The study was originally published in the June 2021 issue of the International Journal of Infectious Diseases.

Related Links:

King Mongkut’s University of Technology Thonburi
SD BIOLINE
QIAGEN