IgA Monoclonal Gammopathy with Pseudohyperphosphatemia.

Monoclonal gammopathies (MGs) reflect conditions in which abnormal amounts of immunoglobulins are produced by a clone that developed from a single pro-B germ cell. They range from asymptomatic, benign disorders such as monoclonal gammopathy of undetermined significance to malignant plasma cell and lymphoid disorders, including multiple myeloma and Waldenstorm macroglobulinemia. The identification of the particular subtype of immunoglobulin molecule is done by serum immunofixation by use of specific antisera directed against different subtypes of immunoglobulin classes. However depending upon the characteristic position taken up by migrating M band on protein electrophoresis due to its molecular weight and charge, serum protein electrophoresis can itself reveal the nature of the immunoglobulin without the need to do serum immunofixation. IgA mostly migrates to beta globulin region and may often be missed out for lack of a sharp, discrete M band in gamma globulin region. Systemic manifestations of MG can be attributed to the physicochemical properties of the monoclonal immunoglobulin, to its antibody activity or to other mechanisms. We describe a case of IgA MG with pseudohyperphosphatemia. © Association of Clinical Biochemists of India 2020.