What does a hepatitis B core antibody (HBcAb) reactive result indicate and how is it managed?

From the Guidelines

A hepatitis B core antibody (HBcAb) reactive result indicates previous or ongoing exposure to hepatitis B virus (HBV), and management depends on other serological markers, with the most recent guidelines recommending antiviral prophylaxis for HBsAg-positive patients and consideration of prophylaxis for HBcAb-positive patients undergoing immunosuppressive therapy 1. This antibody develops during acute infection and typically remains detectable for life, even after recovery. If hepatitis B surface antigen (HBsAg) is positive, this indicates current infection requiring further evaluation with HBV DNA testing and possible antiviral therapy such as entecavir 0.5mg daily or tenofovir 300mg daily for chronic infection. If HBsAg is negative but hepatitis B surface antibody (HBsAb) is positive, this pattern suggests resolved infection with immunity, requiring no specific treatment. If both HBsAg and HBsAb are negative (isolated core antibody), this could represent resolved infection with waning immunity, occult HBV infection, or a false-positive result. In this case, HBV DNA testing may be warranted to rule out occult infection. Patients with isolated core antibody should be monitored periodically and may need HBV prophylaxis if immunosuppressed, as recommended by recent guidelines 1. The core antibody appears early in infection and persists because the immune system continues to encounter core antigen throughout the course of infection, making it a reliable marker of HBV exposure but requiring additional testing to determine current infection status and appropriate management. Key considerations include the risk of HBV reactivation in patients undergoing immunosuppressive therapy, particularly those with HBsAg or HBcAb positivity, and the potential benefits of antiviral prophylaxis in preventing reactivation and related complications 1. Overall, the approach to managing a patient with a reactive HBcAb result should be individualized based on their specific serological profile, clinical context, and risk factors for HBV reactivation.

From the Research

Hepatitis B Core Antibody Reactive Result

A hepatitis B core antibody (HBcAb) reactive result indicates that an individual has been exposed to the hepatitis B virus (HBV) at some point in their life. This exposure can be due to a current or past infection [ 2, 3 ].

Interpretation of HBcAb Reactive Result

The interpretation of a HBcAb reactive result depends on the presence of other hepatitis B markers, such as hepatitis B surface antigen (HBsAg) and hepatitis B surface antibody (anti-HBs).

• If HBsAg and anti-HBs are both negative, the HBcAb reactive result may indicate a past infection that has been cleared, or it may be a false-positive result [ 2 ].
• If HBsAg is positive, the HBcAb reactive result indicates a current infection [ 3 ].
• If anti-HBs is positive, the HBcAb reactive result indicates a past infection that has been cleared [ 4 ].

Management of HBcAb Reactive Result

The management of a HBcAb reactive result depends on the individual's clinical presentation and medical history.

• If the individual is asymptomatic and has no history of liver disease, no further action may be necessary [ 5 ].
• If the individual has a history of liver disease or is symptomatic, further testing and evaluation may be necessary to determine the cause of the HBcAb reactive result [ 6 ].
• In some cases, hepatitis B vaccination and subsequent measurement of anti-HBs may be used to identify evidence of past infection and exclude chronic infection [ 2 ].

Clinical Implications

A HBcAb reactive result has been associated with an increased risk of cirrhosis and hepatocellular carcinoma in patients with nonalcoholic fatty liver disease [ 5 ].

• The presence of HBcAb may also be used to guide treatment initiation and monitoring in patients with chronic hepatitis B [ 3 ].
• The clinical implications of a HBcAb reactive result should be interpreted in the context of the individual's overall clinical presentation and medical history.

Key Points

• A HBcAb reactive result indicates exposure to HBV at some point in life.
• Interpretation of the result depends on the presence of other hepatitis B markers.
• Management depends on clinical presentation and medical history.
• HBcAb reactive result has been associated with increased risk of cirrhosis and hepatocellular carcinoma in patients with nonalcoholic fatty liver disease.