Regarding the serological markers of hepatitis B infection, all of the following statements are correct EXCEPT:

Explanation

## Hepatitis B Serological Markers — Timeline & Interpretation **Key Point:** **HBsAg** is the **earliest** detectable serological marker of acute hepatitis B infection, appearing 1–10 weeks after exposure, even before symptoms or elevated liver enzymes. Anti-HBc IgM appears shortly after HBsAg and is the earliest marker of the **host immune response**, but it is NOT the earliest serological marker overall. ### Serological Marker Sequence in Acute HBV Infection | Marker | Appearance | Significance | Duration | |--------|-----------|--------------|----------| | **HBsAg** | **First (1–10 weeks post-exposure)** | Earliest marker of infection | Weeks–months (acute); persistent (chronic) | | **Anti-HBc IgM** | 2nd (after HBsAg, ~4–10 weeks) | Marker of acute infection; present in window period | ~6 months | | **HBeAg** | During HBsAg phase | High viral replication, high infectivity | Variable | | **Anti-HBe** | After HBeAg clearance | Lower viral replication | Persistent | | **Anti-HBs** | After HBsAg disappears | Indicates recovery & immunity | Long-lasting | **High-Yield:** In acute HBV, the **window period** (HBsAg negative, anti-HBs not yet appeared) is when **anti-HBc IgM alone** detects infection — but this does not make it the "earliest" marker; HBsAg precedes it. ### Why Each Statement Is Correct (Except One) 1. **HBeAg positivity** → High viral replication, high infectivity ✓ (Correct — per Harrison's Principles of Internal Medicine) 2. **Anti-HBc IgM is the earliest marker** ✗ **(INCORRECT — this is the answer)** — HBsAg appears first; anti-HBc IgM appears after HBsAg 3. **Anti-HBs appears after HBsAg clearance and confers immunity** ✓ (Correct — standard textbook teaching; anti-HBs is the marker of recovery and long-term immunity per Robbins & Harrison) 4. **HBsAg persistence >6 months = chronic HBV** ✓ (Correct — standard WHO/textbook definition) **Clinical Pearl (Harrison's / Robbins):** The correct sequence of HBV markers is: **HBsAg → Anti-HBc IgM → HBeAg → Anti-HBe → Anti-HBc IgG → Anti-HBs**. HBsAg is detectable 1–10 weeks post-exposure, well before anti-HBc IgM. Anti-HBc IgM is the key marker during the **window period** (when HBsAg has cleared but anti-HBs has not yet appeared), but it is not the earliest marker of infection. **Warning:** Do not confuse "earliest marker of acute infection detectable in the window period" (anti-HBc IgM) with "earliest serological marker to appear" (HBsAg). This is a classic NEET PG distinction.