Application of a Dengue NS1 antigen based rapid diagnostic test to screen dengue virus infection in clinical settings in Indonesia.

Background: Dengue virus (DENV) is hyperendemic in Indonesia and of high public health concern globally. Without an effective antiviral therapy, an accurate diagnosis of the four viruses, DENV1-4, is crucial for patient management and outcome. We aim to assess the diagnostic accuracy and usefulness of a commercial DENV antigen rapid diagnostic test kit in point-of-care conditions.

Design and methods: Six-hundred-forty-six patients with fever or history of fever, and without leukocytosis, were enrolled from Tabanan General Hospital, Bali in 2017-2018. All sera were tested for DENV NS1 antigen using the Standard Diagnostics Bioline NS1 Ag rapid test kit and Flavivirus genus specific RT-PCR. Positive specimens were further confirmed using DENV multiplex RT-PCR.

Results: DENV was detected in 10.4% (67/646) of enrolled patients by molecular assays. Only 41 of the positives were found to be positive by the NS1 rapid test. Our findings indicate that the kit was the most sensitive in the first 2 days after disease onset with sensitivity > 75%, and declining at day 3 with a sensitivity of <60%. In addition, the kit was found to be the most sensitive to DENV-2 and least sensitive to DENV-4. Overall, the kit had a sensitivity of 59.7% [95% CI: 44.5-74.9] and specificity of 99.8% [95% CI: 99.5-100.0].

Conclusions: Our evaluation indicated that the rapid diagnostic test is useful for both surveillance and initial detection of DENV infection in community settings. However, it should be supplemented with additional diagnostic methods to ensure accurate confirmation for patient management.