Which technique is used to quantify specific immunoglobulin classes?

Which technique is used to quantify specific immunoglobulin classes?

• A. Immunonephelometry
• B. Serum protein electrophoresis
• C. Isoelectric focusing
• D. Immunoelectrophoresis

Answer: (A)

Immunonephelometry is used to quantify specific immunoglobulin classes because it measures the amount of antibody–antigen complexes formed in the reaction and converts that signal into an exact concentration. In this method, serum immunoglobulins of a target class (for example, IgG, IgA, or IgM) react with class-specific antisera to form immune complexes. The light scattered by these complexes is measured in a nephelometer, and the signal is proportional to the immunoglobulin concentration, which is determined against a standard curve. This approach is highly sensitive and specific for each immunoglobulin class, allowing precise quantification. Serum protein electrophoresis separates serum proteins into bands to give a profile and can indicate abnormalities in the gamma region or overall protein distribution, but it doesn’t provide accurate, class-specific concentrations. Isoelectric focusing separates proteins by their isoelectric points and is mainly used for pattern analysis or characterization rather than exact quantitation. Immunoelectrophoresis combines electrophoresis with antibody diffusion to identify reactions and patterns; it’s informative but generally not used for precise concentration measurements.

Immunonephelometry is used to quantify specific immunoglobulin classes because it measures the amount of antibody–antigen complexes formed in the reaction and converts that signal into an exact concentration. In this method, serum immunoglobulins of a target class (for example, IgG, IgA, or IgM) react with class-specific antisera to form immune complexes. The light scattered by these complexes is measured in a nephelometer, and the signal is proportional to the immunoglobulin concentration, which is determined against a standard curve. This approach is highly sensitive and specific for each immunoglobulin class, allowing precise quantification.

Serum protein electrophoresis separates serum proteins into bands to give a profile and can indicate abnormalities in the gamma region or overall protein distribution, but it doesn’t provide accurate, class-specific concentrations. Isoelectric focusing separates proteins by their isoelectric points and is mainly used for pattern analysis or characterization rather than exact quantitation. Immunoelectrophoresis combines electrophoresis with antibody diffusion to identify reactions and patterns; it’s informative but generally not used for precise concentration measurements.