Hepatitis B Core Antibody IgM (Anti HBc-IgM)
Pinpointing "When" the Infection Happened
The Hepatitis B Core Antibody IgM test is a specific diagnostic tool used to determine how recently a person was infected with Hepatitis B.
While the standard screening test (HBsAg) tells us if the virus is present, the Core IgM tells us when it arrived. "IgM" antibodies are the body's "first responders." They appear shortly after infection and usually disappear within 6 months. Therefore, a positive result indicates a new (acute) infection.
Why Is This Test Unique?
This test is not for general screening; it is a "Problem Solver." Doctors order it for three critical reasons:
To Distinguish Acute vs. Chronic:
- If a patient tests positive for Hepatitis B, doctors need to know if they just caught it (Acute) or if they have had it for years (Chronic).
- Positive IgM = Recent Infection (Acute).
- Negative IgM = Old Infection (Chronic).
To Detect the "Window Period":
- There is a strange gap in Hepatitis B infections called the "Window Period." This occurs when the virus (HBsAg) disappears from the blood, but the immunity antibodies (Anti-HBs) haven't appeared yet.
- During this gap, Anti-HBc IgM is often the ONLY positive marker that proves infection occurred.
To Diagnose "Flare-Ups":
- In rare cases, people with chronic Hepatitis B can have a sudden reactivation of the virus. This test helps diagnose these flare-ups
