What indicates multiple myeloma in immunoelectrophoresis test?

In immunoelectrophoresis, multiple myeloma is indicated by the presence of a monoclonal spike or band in the gamma globulin region. This abnormal band represents the overproduction of a single type of immunoglobulin (usually IgG or IgA) by the myeloma cells. The presence of a monoclonal spike is a characteristic finding in multiple myeloma and helps in diagnosing the condition.