A patient presented with acute onset of jaundice and raised aminotranferases. Preliminary serology repo showed HBsAg positivity. On fuher testing, which of the following is least likely to be found in this patient?
## **Core Concept**
The patient's presentation with acute onset jaundice and raised aminotransferases along with HBsAg positivity suggests an acute hepatitis B infection. HBsAg (Hepatitis B surface antigen) is a marker of hepatitis B virus (HBV) infection. The presence of HBsAg indicates that the patient is infectious.
## **Why the Correct Answer is Right**
In acute hepatitis B infection, we typically expect to see HBsAg, IgM anti-HBc (Immunoglobulin M antibody to hepatitis B core antigen), and sometimes HBeAg (Hepatitis B e-antigen) which indicates viral replication and high infectivity. Anti-HBs (antibody to hepatitis B surface antigen) usually appears later in the course of infection, often after the disappearance of HBsAg, indicating recovery and immunity. Therefore, the presence of anti-HBs along with HBsAg would be unusual in the acute phase.
## **Why Each Wrong Option is Incorrect**
- **Option A:** IgM anti-HBc is expected in acute hepatitis B infection, as it is an early marker of acute infection.
- **Option B:** HBeAg can be present in acute hepatitis B, especially if the patient is in the viral replication phase.
- **Option C:** HBV DNA can be detected in acute hepatitis B infection, indicating viral replication.
- **Option D:** Anti-HBs is the correct answer because it is **least likely** to be found alongside HBsAg in acute hepatitis B infection. Anti-HBs typically appears later, signifying recovery.
## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is the serological window in hepatitis B, where HBsAg has disappeared but anti-HBs has not yet appeared, which can sometimes cause diagnostic confusion. However, in acute infection, the presence of IgM anti-HBc helps differentiate it from a chronic infection or vaccination-induced immunity.
## **Correct Answer:** D. Anti-HBs.