Test Details: Urine immunofixation is a test that looks for abnormal proteins in urine. In particular, it looks for an abnormal protein known as M-protein. An M-protein is a kind of abnormal immunoglobulin created by plasma cells, which are a type of white blood cells. This test is used for diagnosis of conditions such as Amyloidosis, Multiple Myeloma, Waldenstrom Macroglobulinemia