A laboratory receives a serum sample labelled 'day 1 of jaundice' from a patient with suspected hepatitis A. The MOST sensitive test to confirm acute HAV infection is:
- A HAV IgG antibody (anti-HAV IgG)
- B HAV IgM antibody (anti-HAV IgM) ✓
- C HAV RNA by RT-PCR
- D Serum alanine aminotransferase (ALT) level
Correct answer: B. HAV IgM antibody (anti-HAV IgM)
Explanation
Anti-HAV IgM is the serological marker of acute HAV infection and is detectable from the onset of symptoms through approximately 3–6 months. HAV RNA by RT-PCR peaks even earlier (in the faecal incubation phase) but is rarely used clinically. Anti-HAV IgG indicates past infection or vaccination, not current acute disease. ALT elevation is a liver injury marker, not specific to HAV. For practical diagnostic confirmation, anti-HAV IgM is the standard first-line test.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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