Acute infection of hepatitis B virus is diagnosed by –
**Core Concept**
Hepatitis B virus (HBV) infection is diagnosed by detecting the presence of viral antigens or antibodies in the blood. The diagnosis of acute HBV infection is crucial for initiating appropriate treatment and preventing transmission to others.
**Why the Correct Answer is Right**
Acute HBV infection is diagnosed by detecting the presence of the hepatitis B surface antigen (HBsAg) and the IgM antibody to hepatitis B core antigen (IgM anti-HBc). HBsAg is a protein on the surface of the virus, while IgM anti-HBc is an antibody produced in response to the core antigen. The presence of both HBsAg and IgM anti-HBc indicates an acute infection. The IgM antibody is used to differentiate between acute and chronic infection, as chronic infection is characterized by the presence of IgG antibodies.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not specify the correct markers for acute HBV infection.
**Option B:** This option is incorrect as it refers to a chronic infection marker (IgG anti-HBc) rather than an acute infection marker.
**Option C:** This option is incorrect as it does not specify the correct markers for acute HBV infection.
**Clinical Pearl / High-Yield Fact**
It is essential to note that the presence of HBsAg alone does not confirm acute infection, as it can also be present in chronic infection. The presence of IgM anti-HBc is a crucial marker for diagnosing acute HBV infection.
**Correct Answer: D. HBsAg and IgM anti-HBc.**