From the Guidelines
When both Hepatitis B surface antigen (HBsAg) and Hepatitis B surface antibody (HBsAb) are positive, it typically indicates a complex clinical scenario that may represent a recovering acute infection, chronic infection with immune escape mutants, or a false positive result, necessitating further testing for clarification. According to the 2021 guidelines on sexually transmitted infections treatment 1, the interpretation of serologic test results for hepatitis B virus infection is crucial for determining the clinical status of the patient. The table provided in the guidelines outlines various serologic markers and their interpretations, but it does not directly address the scenario where both HBsAg and HBsAb are positive.
However, understanding the implications of each marker is essential:
- HBsAg positivity typically indicates current infection, either acute or chronic.
- HBsAb positivity usually signifies immunity, either from past infection or vaccination.
Given this, the coexistence of both markers suggests a need for careful evaluation to determine the exact nature of the infection and the appropriate management strategy. This might involve additional tests such as HBV DNA levels, HBeAg, anti-HBe, and possibly repeat testing of both HBsAg and HBsAb to confirm the results and rule out any laboratory errors.
The clinical approach should prioritize confirming the diagnosis and assessing the patient's immune status and viral replication. A hepatology or infectious disease consultation is advisable to interpret these results properly and determine the appropriate management, considering the potential for immune escape mutants or other complex scenarios that may affect treatment decisions and patient outcomes. Immediate treatment should not be initiated without a clear understanding of the patient's clinical status, as this could lead to inappropriate or potentially harmful interventions.
From the Research
Interpretation of Hepatitis B Surface Antigen and Surface Antibody Results
- The presence of both Hepatitis B surface antigen (HBsAg) and Hepatitis B surface antibody (HBsAb) in an individual can be interpreted in several ways, as indicated by studies 2, 3, 4, 5, 6.
- HBsAg is typically considered the hallmark of HBV infection, and its persistence for more than 6 months suggests chronic HBV infection 2.
- The coexistence of HBsAg and HBsAb can occur due to various reasons, including interference from endogenous antibodies, the presence of HBsAg from one strain and HBsAb from another, or the presence of low levels of HBsAb that are neutralized and not recognized by the solid-phase HBsAg in the assay 3.
- Studies have shown that the coexistence of HBsAg and HBsAb can be found in patients with chronic HBV infection, and this serological status can remain stable for an extended period 4.
- The presence of HBsAb in patients with chronic HBV infection does not necessarily lead to the clearance of HBsAg, and the HBV isolates from these patients may not exhibit significant differences in amino acid substitutions within the HBsAg 4.
Clinical Implications
- The detection of both HBsAg and HBsAb in a patient can have significant clinical implications, including the potential for fulminant hepatitis, as reported in a study 5.
- The prognosis of patients with both HBsAg and HBsAb detected simultaneously is generally poor, with a lower survival rate compared to those with no evidence of HBV infection 5.
- Screening for hepatitis B serologic markers, including HBsAg and HBsAb, is considered an efficient and cost-effective method for identifying individuals with HBV infection or immunity 6.
- Postvaccination testing for hepatitis B seroconversion is recommended in patients with chronic liver disease, especially in those with more advanced disease, due to the lower rate of seroconversion in these patients 6.