Related Experiment Video
Updated: May 3, 2026
Dried Blood Spots - Preparing and Processing for Use in Immunoassays and in Molecular Techniques
Published on: March 13, 2015
Resolving a case of concurrent hepatitis B virus surface antigen (HBsAg) and surface antibody (HBsAb)
Thomas Kampfrath1, Saeed A Jortani2, Stanley S Levinson3
1Department of Pathology and Laboratory Medicine, Santa Clara Valley Medical Center, San Jose, CA, United States.
Background:
In most cases, patients appear to recover from acute hepatitis B virus (HBV) infection and do not exhibit the surface antigen (HBsAg). Chronic carriers are positive for HBsAg but HBsAb is usually not present. After acute infection only HBsAb remains. The presence of both HBsAg and HBsAb is unusual.
Methods:
We report on a patient whose results were analytically and clinically discrepant--positive for HBsAg and HBsAb on one testing platform but only HBsAg on another platform.
Results:
Reasons for this result: 1) Interference from endogenous antibodies; 2) HBsAg is from one strain and HBsAb is from another: and 3) The presence of HBsAb and HBsAg. Growing evidence indicates that both may be present in many patients. Low HBsAb may be neutralized and not recognized by the solid-phase HBsAg in the assay. Likewise, low HBsAg may be neutralized by HBsAb. It remains unclear whether HBsAg is always cleared after acute infection.
Conclusions:
Testing indicated that both HBsAb and HBsAb were present. The data shows that different testing platforms may produce different results depending on the kinetics, the exposure of the capture HBsAg and the extent of endogenous HBAg/HBsAb. We demonstrate a simple way to rule out test interference to presumptively identify true HBsAb.
