From the Guidelines
The antibody checked for an active Hepatitis B infection is Hepatitis B surface antigen (HBsAg) and IgM antibodies to Hepatitis B core antigen (anti-HBc IgM). This is based on the most recent evidence from 1, which indicates that HBsAg is the primary serological marker used to identify current HBV infection, and anti-HBc IgM appears early in acute infection. When HBsAg is detected in a patient's serum, it indicates the virus is actively replicating in the liver. For a complete assessment of HBV infection status, additional markers are typically tested alongside HBsAg, including Hepatitis B e antigen (HBeAg), which indicates high viral replication and infectivity. HBsAg usually appears in the blood 1-10 weeks after exposure to the virus and before symptoms develop. If HBsAg persists for more than 6 months, this indicates chronic HBV infection. Testing for HBsAg is essential for diagnosing both acute and chronic HBV infections, guiding treatment decisions, and preventing transmission to others. Some key points to consider when interpreting serologic markers for HBV infection include:
- HBsAg: indicates current HBV infection
- Anti-HBc IgM: indicates acute or recent HBV infection
- HBeAg: indicates high viral replication and infectivity
- Anti-HBe: indicates loss of replicating virus, although reversion to HBeAg positivity can occur, as noted in 1 and 1. It's also important to note that the presence of IgM anti-HBc can persist during viral replication at low levels, and persons with exacerbations of chronic infection can test positive for IgM anti-HBc, as mentioned in 1. However, the most recent and highest quality study 1 provides the most relevant guidance on the interpretation of serologic markers for HBV infection.
From the Research
Antibody for Active Hepatitis B Infection
To determine an active Hepatitis B (HB) infection, the following antibody is checked:
Characteristics of Anti-HBc IgM
The characteristics of anti-HBc IgM include:
- Present in high titer during acute hepatitis B infection 4
- Indicates recent or ongoing hepatitis B infection 2, 3
- Useful in differentiating between hepatitis B infection with or without HBsAg and acute non-A, non-B hepatitis 2
- Presence of anti-HBc IgM is associated with the degree of inflammatory activity in patients with HBsAg-positive chronic liver disease 3
Clinical Significance of Anti-HBc IgM
The clinical significance of anti-HBc IgM includes:
- Diagnostic significance in acute HBsAg positive hepatitis 5
- Prognostic significance in acute HBsAg positive hepatitis 5
- Helps in identifying previously unrecognized long-term carriers of HBsAg 5
Detection and Interpretation
The detection and interpretation of anti-HBc IgM, along with other serological markers such as HBsAg and anti-HBcIgG, are crucial for the clinical classification and epidemiological surveillance of HBV infection 6