Question

What may be seen in a case of acute hepatitis B infection?

• A. Dane particle
• B. HBsAg
• C. IgM anti-HBc
• D. Anti-HBe

Hint:

Dane particle, HBsAg and anti-HBe can occur at multiple stages, but IgM anti-HBc is specific to the acute phase.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
This question again deals with hepatitis B markers, but this time it asks which finding is the one that specifically defines a case as acute, rather than simply being present at some point during infection.

Step 2: Key Concept:
Several hepatitis B markers, such as the Dane particle (the complete infectious virion), HBsAg, and anti-HBe, can appear at multiple stages of infection, acute or chronic, and so cannot by themselves diagnose an acute case. IgM anti-HBc, however, is only found in the first several months after infection, which is what makes it diagnostic of the acute phase specifically.

Step 3: Detailed Explanation:
The Dane particle is simply the complete, infectious hepatitis B virion, made of the outer envelope (HBsAg) and inner core (HBcAg with viral DNA and polymerase). It circulates whenever the virus is actively replicating, in both acute and chronic infection, so its presence does not confirm acuteness.
HBsAg appears in acute infection but also persists in chronic carriers for years, so on its own it cannot distinguish acute from chronic disease.
Anti-HBe usually appears later, as the disease starts to resolve or in the inactive carrier state, and its presence does not specifically define an acute infection.
IgM anti-HBc is different: it rises within weeks of exposure and disappears by about six months, so its presence is the specific laboratory sign that pins the infection down to the acute or recent window. It is also the key marker used to diagnose acute hepatitis B during the window period, when HBsAg may already be undetectable.

Step 4: Final Answer:
IgM anti-HBc is the finding that is specifically seen in, and diagnostic of, acute hepatitis B infection.