Complete response assessment by electrophoresis: examples of pitfalls. Patient with an initial spike in the gammaglobulins region (M-IgG) (A) was first considered in n-CR (positive immunofixation and normal electrophoresis). The tracing was reviewed by an independent expert committee who noticed the persistence of a small spike (B, ) and reclassified this case as VGPR. (C) Post-ASCT oligoclonal gammopathy (). Because one of the small spikes corresponded to the same isotype as the original M-component, this patient was considered in VGPR.