Quantification of Monoclonal Immunoglobulins by Immunochemical and Densitometry Techniques

In comparing four currently available immunochemical methods for immunoglobulin quantification, i.e. radial immunodiffusion (RID), rate nephelometry (RN), laser nephelometry (LN) and turbidimetry (T), highly divergent results were obtained for monoclonal immunoglobulins. Comparison with data obtained by densitometric scanning (D) of the serum protein electrophoresis on cellulose acetate showed that these immunochemical techniques cannot be recommended for the quantification of monoclonal immunoglobulins, they may however remain useful for assessing relative changes in concentration during treatment.