NS1 Rapid Card Test for Dengue Detection: Insights from the 2023 Outbreak in Bangladesh

Ruksana Raihan,1 Richard Malo,2 Younuch Mia Jewel,2 Atiquzzaman,3 Farhana Afrin Ferdousy,4 Syed Abul Hassan Md Abdullah,5 Saif Ullah Munshi,6 Mohammad Jahidur Rahman Khan,7 Aoveek Hossain,8 Shahed Sheikh Shawon,9 Redoy Ranjan,10,11 Md. Abdullah Yusuf,12 KZ Mamun13 1Department of Microbiology, US Bangla Medical College and Hospital, Dhaka, Bangladesh and Molecular Lab, Laboratory Quest AD, Dhaka, Bangladesh; 2Life Science Division, OMC, Dhaka, Bangladesh; 3Department of Medicine, Dhaka National Medical College, Dhaka, Bangladesh; 4Ahsania Mission Cancer and General Hospital, Dhaka, Bangladesh; 5Safetynet Bangladesh, Dhaka, Bangladesh; 6Department of Virology, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh; 7Department of Microbiology, Shaheed Suhrawardy Medical College, Dhaka, Bangladesh; 8Department of Microbiology, Monash University, Subang Jaya, Selangor Darul Ehsan, Malaysia; 9Department of Biochemistry, Genome Dx Corporation, Dhaka, Bangladesh; 10Department of Biological Sciences, Royal Holloway University of London, London, UK; 11Department of Cardiac Surgery, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh; 12Department of Microbiology, National Institute of Neurosciences and Hospital, Dhaka, Bangladesh; 13Department of Microbiology, Dhaka Medical College, Dhaka, BangladeshCorrespondence: Ruksana Raihan, Department of Microbiology, US Bangla Medical College and Hospital, Dhaka, Bangladesh and Consultant, Molecular Lab, Laboratory Quest AD, Dhaka, Bangladesh, Email [email protected]: Dengue poses a serious public health challenge in Bangladesh, with the 2023 outbreak resulting in over 1700 deaths, the highest on record. Despite apparent symptoms, many patients tested negative on the NS1 rapid antigen test, the primary diagnostic tool. This study assesses the reliability of the NS1 rapid test results by analyzing its sensitivity, specificity, and predictive values using RT-PCR as the gold standard. It also explores how viral serotypes and secondary infections may impact test performance, especially in NS1-negative cases.Methods: This cross-sectional study recruited febrile patients at two tertiary hospitals in Dhaka, Bangladesh, within 24 hours to 7 days of fever onset. Patients were selected based on physician-advised NS1 antigen testing, without restrictions on age, sex, or occupation. NS1 antigen test reports were collected from hospitals, and RNA testing via RT-PCR was conducted on all samples. Additional IgG and IgM tests were carried out for NS1-negative, RT-PCR-positive cases, and serotyping was performed on all RT-PCR-positive samples.Results: Of the 194 samples tested, 65 (33.5%) were RT-PCR positive for dengue. Among these, 25 (38.5%) were NS1-negative. Most RT-PCR-positive cases were male (67.7%), with the 16– 45 age group most affected. Symptoms like body aches (83.1%) and headaches (70.8%) were common. The predominant serotype was DEN-2 (97.5% in NS1-positive and 84% in NS1-negative cases), known for lower NS1 sensitivity. NS1 test sensitivity, specificity, PPV, and NPV were 61%, 97%, 91%, and 83%, respectively. Early IgG positivity in NS1-negative cases suggested secondary infections.Conclusion: Despite the high specificity of NS1 rapid tests, moderate sensitivity demands alternative diagnostics like RT-PCR, which are crucial for better dengue management, especially in the presence of DEN-2 infections and associated secondary infections in Bangladesh.Keywords: dengue, NS1 rapid test, RT-PCR, serotypes, DEN-2 infections