A 27-year-old woman presents with fever, myalgia and retro-orbital pain since 48 hours. Her physician suspects dengue and wants the most sensitive confirmatory test at this stage of illness. Which test should be ordered?

• A NS1 antigen detection ✓
• B Dengue-specific IgM ELISA
• C Dengue-specific IgG ELISA
• D Haemagglutination inhibition titre

Explanation

NS1 antigen is detectable from day 1 of fever and remains positive through roughly the first 5 to 9 days, making it the test of choice in the febrile phase before defervescence. IgM antibodies generally become detectable around day 5 and peak in the convalescent phase, so IgM ELISA would be falsely reassuring on day 2. IgG rises later still and persists for years, so a single titre cannot confirm acute infection.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.