What are the underlying immunological or molecular principles used in the HBeAg Rapid Test for the detection of HBeAg?

The HBeAg Rapid Test detects hepatitis B e antigen (HBeAg) using immunological principles, specifically through antibody-antigen interactions. Here's a breakdown of the underlying immunological principles involved:

Antibody Production:
Monoclonal antibodies specific to HBeAg are produced and immobilized as capture reagents on the test strip or membrane of the rapid test device. These antibodies are designed to bind specifically to HBeAg antigens.

Sample Application and Flow:
A patient's serum or plasma sample, potentially containing HBeAg, is applied to the test strip. If HBeAg is present in the sample, it will bind to the immobilized monoclonal antibodies through antigen-antibody interactions.

Conjugate Pad:
The test strip also contains a conjugate pad where colloidal gold particles (or other detectable markers) are conjugated with monoclonal antibodies against HBeAg. These antibody-gold conjugates act as detection reagents.

Flow of Reagents:
Upon sample application, if HBeAg is present, it binds to the immobilized antibodies on the test strip. The HBeAg-antibody complex continues to flow along the strip.

Signal Generation:
As the complex flows past the control line (where immobilized antibodies capture excess conjugate antibodies) and the test line (where immobilized antibodies capture HBeAg), the colloidal gold particles or other markers on the conjugate antibodies bind to the immobilized antibodies at the test and control lines, forming visible lines or signals.

Result Interpretation:
The presence of a colored line at both the control line and the test line indicates a positive result, indicating the presence of HBeAg in the sample. A line at the control line only indicates a negative result, meaning no HBeAg was detected.

The immunological principles of the HBeAg Rapid Test leverage specific antibody-antigen interactions to detect the presence of HBeAg in biological samples quickly and qualitatively. This method is designed for rapid point-of-care testing, providing healthcare providers with timely diagnostic information for hepatitis B virus infection management.