Hepatitis B Core Antibody (IgM)

The Hepatitis B Core Antibody (IgM), also known as anti-HBc IgM, is a blood test used to detect a recent or acute infection with the hepatitis B virus (HBV). It is one of the earliest markers of hepatitis B infection and helps distinguish between acute and chronic HBV infection.

1. What Is Hepatitis B Core Antibody (IgM)?

• Anti-HBc IgM is an antibody produced in response to the core antigen of the hepatitis B virus.

• It appears shortly after infection and typically remains detectable for about 6 months.

• It is a specific marker for recent (acute) infection and is not present in vaccinated individuals.

2. Why Is the Anti-HBc IgM Test Performed?

This test is used to:

• Diagnose acute or recent HBV infection.

• Distinguish between acute and chronic hepatitis B.

• Evaluate unexplained liver inflammation (e.g., elevated liver enzymes, jaundice).

• Screen blood donors or individuals at risk of transmitting hepatitis B.

3. How to Interpret Anti-HBc IgM Results

🔹 Positive Anti-HBc IgM:

• Indicates a recent or acute hepatitis B infection (typically within the last 6 months).

• May be seen during the 'window period' when other hepatitis B markers are temporarily absent.

🔹 Negative Anti-HBc IgM:

• Suggests no recent HBV infection or a chronic phase where IgM is no longer present.

• May still require further testing (e.g., anti-HBc total, HBsAg, anti-HBs) to determine overall HBV status.

4. What Can Affect Anti-HBc IgM Results?

• Timing of the test (too early or too late may yield false-negative results).

• Immune status of the patient (e.g., immunocompromised individuals may have a delayed response).

• Concurrent liver disease or coinfections.

5. How Is the Test Performed?

• A blood sample is drawn from a vein.

• No fasting or special preparation is typically needed.

6. When to See a Doctor

🚨 Contact your healthcare provider if you:

• Have symptoms of hepatitis (e.g., jaundice, fatigue, dark urine, abdominal pain).

• Were recently exposed to someone with hepatitis B.

• Have abnormal liver function tests or are at risk for HBV.

🔹 Key Takeaways

✅ Anti-HBc IgM is a reliable marker of recent hepatitis B infection.

✅ It is used alongside other tests to confirm diagnosis and guide treatment decisions.

✅ Early detection of hepatitis B is important for preventing complications and transmission.