The solid phase radioimmunoassay technique for hepatitis B (surface) antigen: effects of progressive modification

Area of Science:

• Hepatology
• Immunology
• Clinical Diagnostics

Background:

• Hepatitis B virus (HBV) infection remains a significant global health concern.
• Accurate detection of hepatitis B surface antigen (HBsAg) is crucial for diagnosis and management.
• Counterelectrophoresis (CEP) and solid phase radioimmunoassay "sandwich" technique (SPRIA) are common HBsAg detection methods.

Purpose of the Study:

• To evaluate the specificity of different modifications of the SPRIA technique for HBsAg detection.
• To compare the performance of SPRIA modifications against counterelectrophoresis (CEP).
• To identify optimal SPRIA conditions for minimizing false-positive HBsAg results.

Main Methods:

• Serum specimens were tested using CEP and three SPRIA variations.
• Specificity of two SPRIA methods was assessed.
• SPRIA conditions, including temperature, incubation time, and antibody pairings (homologous guinea pig, heterologous guinea pig-human), were varied.

Main Results:

• Out of 688 specimens, 175 were reactive by all methods, and 60 were specifically reactive by two SPRIA modifications.
• The primary SPRIA method (homologous guinea pig antibody) yielded 184 non-specific reactive samples.
• Modifying SPRIA to 45°C with reduced incubation decreased non-specific results to 37.
• Using a heterologous guinea pig-human antibody sandwich eliminated non-specific reactions.

Conclusions:

• SPRIA technique modifications significantly impact the specificity of HBsAg testing.
• Optimizing SPRIA conditions, particularly antibody combinations and incubation parameters, is essential for accurate HBsAg detection.
• The findings provide a basis for improving the reliability of SPRIA assays in clinical settings.