Iga Myeloma with Increased Anion Gap, Pseudo hyperphosphatemia and Pseudohyponatremia

Mutiple myeloma (MM) is a hematopoietic malignancy characterized by proliferation of a single clone of plasma cells resulting in production of monoclonal immunoglobulins or paraproteins (IgG, IgA or IgM). With elevation in serum paraprotein levels the potential for erroneous laboratory results increases secondary to interference of paraproteins with colorimetric assays 2,3. Paraproteins can alter anion gap (AG) depending on their cationic or anionic properties . A decreased AG is usually observed in MM; however, an increased AG is a rare presentation. We report an unusual presentation of IgA myeloma with an increased anion gap and spurious laboratory findings that included pseudohyperphosphatemia and pseudohyponatremia.