Clinical Information

Monoclonal gammopathies indicate a clonal expansion of plasma cells or mature B lymphocytes that commonly consist of IgG, IgA, and IgM heavy chains. However, these monoclonal proteins may rarely consist of IgD or IgE immunoglobulin heavy chains. Diseases that are associated with monoclonal gammopathies include multiple myeloma, primary systemic amyloidosis, and light-chain deposition disease, as well as premalignant disorders such as smoldering multiple myeloma and monoclonal gammopathy of undetermined significance.

Initial Isotyping or immunofixation identifies the monoclonal immunoglobulin heavy-chain (gamma, alpha, or mu) and/or light-chain type (kappa or lambda). Since IgD and IgE monoclonal gammopathies are rare, they are not part of the initial screening/isotyping.

Since the anti-sera against IgD and IgE are excluded from initial screening methods, this testing should only be ordered on patients with confirmed IgD or IgE monoclonal gammopathy or patients with only free monoclonal kappa or lambda light chains upon initial isotyping. Once the presence of an IgD or IgE heavy chain is excluded, there is no need to continue monitoring with this specialized isotyping assay; rather, continued monitoring via serum protein electrophoresis and traditional isotyping is more appropriate.