Dengue fever diagnosis: On day 1 of fever the most sensitive test is NS1 antigen detection. On day 7, the test with highest sensitivity is:

• A NS1 antigen ELISA
• B IgM antibody capture ELISA (MAC-ELISA) ✓
• C RT-PCR for dengue viral RNA
• D Plaque reduction neutralisation test (PRNT)

Explanation

Dengue diagnosis is time-dependent: NS1 antigen and RT-PCR are positive during the viraemic phase (days 1–5). By day 7, NS1 antigen and viral RNA titres fall below detection thresholds, while IgM antibodies rise (seroconversion), making IgM MAC-ELISA the most sensitive test from day 5–7 onward. A positive IgM MAC-ELISA alone is sufficient for probable dengue diagnosis. PRNT is the gold standard for serotyping but is technically complex and not routine.

Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.