A 30-year-old patient presented with history of jaundice for 30 days. His liver function tests showed bilirubin of 100mg/dI, SGOT/SGPT-1 100/1450, serum alkaline phosphatase-240 IU. He was positive for Hbs Ag. What should be the confirmatory test to establish Acute hepatitis B infection?

**Core Concept**
The underlying principle being tested is the diagnosis of acute hepatitis B infection, which involves understanding the serological markers of hepatitis B virus (HBV) infection. **Hepatitis B surface antigen (HBsAg)** is a marker of current infection, but additional tests are needed to distinguish between acute and chronic infection.

**Why the Correct Answer is Right**
To confirm acute hepatitis B infection, one must look for the presence of **IgM antibody to hepatitis B core antigen (IgM anti-HBc)**, which is a specific marker of acute infection. This antibody appears early in the course of infection and typically remains detectable for up to six months.

**Why Each Wrong Option is Incorrect**
**Option A:** Is incorrect because it is not specified, but typically, other options might include tests that are not specific for acute infection, such as HBsAg alone, which can be present in both acute and chronic infections.
**Option B:** Similarly, without specification, it's hard to judge, but any option not indicating IgM anti-HBc would be incorrect for diagnosing acute infection.
**Option C:** And **Option D:** Without the actual options provided, the reasoning would involve eliminating any choice that does not directly point to a test for IgM anti-HBc.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that the presence of **IgM anti-HBc** is crucial for diagnosing acute hepatitis B infection, as it differentiates acute from chronic infection, where IgG anti-HBc would be the predominant antibody.

**Correct Answer:** D. IgM anti-HBc

✓ Correct Answer: A. IgM Anti-HBc antibody