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Updated: Jun 10, 2026
Portable Paper-Based Immunoassay Combined with Smartphone Application for Colorimetric and Quantitative Detection of Dengue NS1 Antigen
Published on: January 26, 2024
NS1 antigen as an early diagnostic marker in dengue: report from India
Mini Pritam Singh1, Manasi Majumdar, Gagandeep Singh
1Department of Virology, Postgraduate Institute of Medical Education and Research, Chandigarh, India. minipsingh@gmail.com
Abstract:
Detection of specific IgM antibodies by ELISA forms the mainstay for diagnosis of dengue infection. However, IgM antibodies develop after 4 to 5 days of infection. The methods for early diagnosis include virus isolation and reverse transcriptase polymerase chain reaction (RT-PCR) which need a sophisticated laboratory. Another alternative that has recently come up is NS1 antigen detection. The present study compared IgM antibody detection with NS1 antigen for the diagnosis of acute dengue in 87 samples. NS1 antigen could be detected with good sensitivity (71-100%) till day 3 of fever, whereas IgM had a sensitivity of 0% to 50% at this time. On day 4 of illness, both the tests had comparative sensitivity. Beyond day 4, IgM antibody detection was superior to NS1. Both these diagnostic modalities were also compared with RT-PCR in 40 acute samples. NS1 detected additional 15 samples, which were missed by PCR. NS1 antigen is an early diagnostic marker that is feasible in a routine diagnostic laboratory.
Insights
Early dengue diagnosis is improved with NS1 antigen detection, which is more sensitive than IgM antibody tests in the first few days of fever. NS1 antigen testing is a feasible option for routine diagnostic laboratories.
Area of Science:
- Medical diagnostics
- Virology
- Immunology
Background:
- Current dengue diagnosis relies on IgM antibody detection, which becomes positive only 4-5 days post-infection.
- Early dengue diagnosis methods like virus isolation and RT-PCR require specialized laboratory infrastructure.
- NS1 antigen detection has emerged as a promising alternative for early dengue diagnosis.
Purpose of the Study:
- To compare the diagnostic performance of NS1 antigen detection and IgM antibody detection for acute dengue.
- To evaluate the feasibility of NS1 antigen testing in routine diagnostic settings.
Main Methods:
- Comparison of NS1 antigen and IgM antibody detection assays in 87 patient samples.
- Validation against RT-PCR in 40 acute dengue samples.
- Sensitivity analysis based on the day of fever onset.
Main Results:
- NS1 antigen showed high sensitivity (71-100%) from day 1 to day 3 of fever, while IgM sensitivity was low (0-50%).
- Both methods had comparable sensitivity on day 4.
- IgM detection was superior to NS1 beyond day 4.
- NS1 antigen testing identified 15 additional positive cases missed by RT-PCR.
Conclusions:
- NS1 antigen is a valuable early diagnostic marker for dengue, offering higher sensitivity in the initial febrile phase compared to IgM.
- NS1 antigen detection is a practical and feasible method for routine diagnostic laboratories, aiding in earlier patient management.
- Combining NS1 antigen and IgM antibody testing may optimize dengue diagnosis across different stages of illness.
